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HOW TO: Clean, easy and highly nutritious greenwater culture for Daphnia and Moina.

louis_last

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23 Nov 2008
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Edinburgh / Dunbar - Scotland
20210313_155546.jpg


Recently I asked on here whether anybody had experience cultivating the green algae Chlorella vulgaris in freshwater for use in feeding Moina macrocopa cultures. The species is often used in saltwater phytoplankton systems, and is the preferred food for industrial scale Daphnia and Moina production on fish farms in the far east, but nobody seemed to have any details on small scale cultivation for freshwater livefood systems.
I've done some experimentation and found an incredibly simple and easy method for producing useful amounts of highly nutritious greenwater with an absolute minimum of effort - and using products that are easily and cheaply obtained in the UK.

Why Moina? and why Chlorella vulgaris?
Moina species are cultivated in exactly the same way as Daphnia but are smaller, reproduce faster, and can tolerate much higher culture densities than larger Daphnia species. They are also more nutritious than larger daphnia with a higher protein and fat content.
Culture Techniques of Moina : The Ideal Daphnia for Feeding Freshwater Fish Fry highlights the fact that
High population densities of Daphnia can result in a dramatic decrease in reproduction, but this is apparently not the case with Moina. The egg output of Daphniamagna drops sharply at a density as low as 95-115 mature individuals per gallon (25-30/L). The maximum sustained density in cultures of Daphnia reported is 1,900 individuals per gallon (500/L). Moina cultures, however, routinely reach densities of 19,000 individuals per gallon (5,000/L) and are, therefore, better adapted for intensive culture........
..........Although variable, the protein content of Moina usually averages 50% of the dry weight. Adults normally have a higher fat content than juveniles. The total amount of fat per dry weight is 20-27% for adult females and 4-6% for juveniles
Cultures can be very easily maintained on dried bakers yeast but this doesn't provide optimal nutrition and more crucially it's very easy to crash cultures by overfeeding with yeast, particularly in small scale systems or when you're initially working with smaller numbers of Moina. Chlorella vulgaris does not foul the culture water in the same way and contains far more nutrition than yeast. In fact Chlorella is commonly used as a health supplement for humans as it is 50-60% protein and contains all nine essential amino acids as well as vitamin A, Zinc, Magnesium, Iron, Phosphorus, B vitamins and healthy omega 3 as well as caretenoids.

Materials and method
You can find many instructions online for constructing a photobioreactor for intensive phytoplankton cultivation but like me you may be looking for a simpler approach. The primary result of my experimentation is that I've found a cheap and readily available organic fertiliser than can be used to produce healthy uncontaminated Chlorella cultures without any additional equipment. Most of the phytoplankton media offered for sale are prohibitvely expensive - reefphyto.co.uk offers 1000ml of 'Guillards F/2 medium' for £36.98 before delivery and this would make approximately 666 litres of culture water whilst Blades Biological offers just 20ml of 'Algagrow concentrate' sufficient to make only 2 litres of culture water for £7.66 before delivery!
The good news is that I've discovered 'BioBizz fish mix', with an N-P ratio of 5-1 is a sutable organic alternative that can be bought from amazon.co.uk for just £10 delivered and 1 litre of this is sufficient to produce 1000 litres of culture water.
To get started you will need:
1. Two 2 litre bottles of still water. I used coop own brand water, it doesn't need to be fancy and in most cases tap water will suffice. It's the bottle you're really after.
2. One 1000ml bottle of BioBizz fish mix
3. A small starter culture of Chlorella vulgaris. This can be obtained either from Blades Biological (30ml of Chlorella £10.84 + delivery) or from Seahorsebreeder.co.uk in the form of a 'phyto disc' culture on Agar for £18.17 + delivery. I've bought both, and although the phytodisc is more expensive, it represents much better value for money and can be preserved in the fridge as a backup once you've started your culture. Interestingly Chlorella vulgaris can be grown in either salt or freshwater so don't be confused by retailers offering it for use in reef systems.

Once you've got these three things you're good to go and this is really all you need. I was surpised to discover that an air pump to agitate the water seems not to be necessary but may result in faster growth.
All you have to do is add 2ML of your fish mix to 2L of water in a plastic bottle and then innoculate with a small amount of Chlorella and you're set. I place the bottles on a windowsill and shake them for a minute or so a couple of times a day. Once the water is a nice opaque green colour you simply add 95% of it it to your Moina or Daphnia culture before using the remainder to innoculate your second bottle of culture water. In this way you can easily maintain a constant supply of Chlorella with a minimum of effort and by incorporating more bottles or larger 5L containers you can easily scale up production to match the amount of Daphnia or Moina you need to produce.
You must agitate the bottles every day to avoid the culture 'clumping' but If you don't want the hassle then the addition of a cheap air pump avoids this necessity and may boost production. The first starter culture I obtained from Blades biological didn't appear to be 'greenwater' at all as all the chlorella had clumped out and formed a dusty sediment on the bottom of the glass vial. At first it continued to grow in this manner but with daily shaking it quickly seperates and begins to grow as suspended 'greenwater' again.
I'm just sharing this information as it removes a lot of the hassle associated with feeding yeast. Using greenwater you can feed a much more concentrated solution without the same water fouling issues - this means you can perform a large feeding of greenwater every few days or even once a week depending on your culture density and whatever Cladoceran species you're producing will have much higher nutritional value for your fish.
The advantages over an outdoor greenwater bucket or pond is that you avoid contamination with rotifers or any undesirables and know that the single species of algae you're producing has excellent nutritional value whilst many that naturally occur in eutrophic water may not.
Culturing the Moina themselves is equally straightforward and in my experience an air pump is also unnecessary if you use wide flat containers that provide plenty of surface area for air exchange. Moina are well known to thrive in oxygen poor environments due to their capacity to produce haemoglobin so I have no problem producing large amounts in non oxygenated water.

I hope this might prove useful to some of you here. I'm totally sure the method described can be improved upon and I welcome any suggestions but this technique seems valuable purely based on it's simplicity and relatively low startup cost. I found a poorly translated suggestion from an Asian fish breeder that adding some small limestone chips as a 'carbon source' in the Chlorella culture is beneficial and may try it out but I'm not sure of the science behind that.

 

Wookii

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Nottingham
@louis_last this absolutely awesome! I have, for the past several months, been struggling to culture Moina.

I have only had recent success when I bought a small 20 litre tank, a heater and a light for the culturing, and I’ve been daily feeding a yeast and dried Chlorella powder mix.

image.jpg


A live Chlorella mix would be a a far better solution.

When you say the bottles are on a windowsill - how important is the and amount of light to the culture?

Could the culture be kept under artificial light?
 

jaypeecee

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Bracknell
Hi @louis_last

This is really interesting. The last time I cultured Moina (some time ago), it wasn't an overwhelming success. I used dried Spirulina. I just wonder - if the Chlorella vulgaris gets into the destination tank, would there be any possibility of a 'Green Water' bloom occurring? Or, am I overlooking something?

JPC
 

louis_last

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Hi @louis_last

This is really interesting. The last time I cultured Moina (some time ago), it wasn't an overwhelming success. I used dried Spirulina. I just wonder - if the Chlorella vulgaris gets into the destination tank, would there be any possibility of a 'Green Water' bloom occurring? Or, am I overlooking something?

JPC
I think that's unlikely but a real possibility depending on your fertilization regime. Daphnids really do polish the water until it's crystal clear though, I wait until there's not the slightest hint of cloudiness left in the water before harvesting them anyway as a habit from when I was feeding them yeast and at this point there are probably so few free floating cells of Chlorella remaining that the risk really is minimal and on a par with introducing anything new to your tank that might be contaminated with single celled algae.
 

louis_last

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@louis_last this absolutely awesome! I have, for the past several months, been struggling to culture Moina.

I have only had recent success when I bought a small 20 litre tank, a heater and a light for the culturing, and I’ve been daily feeding a yeast and dried Chlorella powder mix.

View attachment 164766

A live Chlorella mix would be a a far better solution.

When you say the bottles are on a windowsill - how important is the and amount of light to the culture?

Could the culture be kept under artificial light?
It really is a much better solution than yeast but you can also still supplement with a little yeast, paprika, gram flour or whatever else takes your fancy for even more nutrient dense moina.
My bottles are on a pretty much west facing windowsill so they get direct sunlight only in the afternoon and I'm on the west coast of scotland so sunlight is in fairly short supply at the moment. I've also tried them under LED lights and it works just fine but for some reason there seems to be more of an issue with clumping under artificial lights although I've not carried out enough tests to make any seriously valid comparison. Interestingly Chlorella specifically can actually be cultivated in the dark or very low light conditions by adding up to 2 grams per litre of glucose to your culture medium but when grown in this way it tends to be yellow and lacks some of the byproducts of photosynthesis that make it more nutritious. I've also got a bottle supplemented with glucose growing that way and it is indeed yellow but I'm scared to feed it as without a proper microscope I can't actually be sure what it is growing in there and it could easily be some other kind of bacteria.
It looks like you have a different species of Moina to me as my adults are still much smaller than daphnia but noticeably larger relative to a red ramshorn than what's shown in your picture. I think you may have Moina micrura as opposed to Moina macrocopa, I'd happily swap you some Chlorella for a small starter if you're interested. Didn't you say you were thinking of creating a vivarium/paludarium too? I'm about to trim mine so If you're up for a swap I can chuck some Marcgravia trimmings and a baby Priumulinia tamiana in with the chlorella as well.
 
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louis_last

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By the way for anyone who can't be bothered with this and just wants to culture Moina with yeast the advice I wish someone had given me before I started was don't worry about underfeeding. If you're anything like me you will crash multiple cultures by either feeding too often, or too much yeast, because you've heard that a lack of food causes them to begin sexual reproduction and Ephippia formation. This is true but it's not remotely a problem compared to a sudden mass die off due to overfeeding. When feeding yeast you really need to make sure that the water is totally crystal clear before you feed again and also that it's only ever slightly cloudy when you do feed, you can put a few leaves or a little bit of hay in the culture as well as some snails to act a a slight buffer for when they clear the water of yeast and even when males do appear it's only ever a few famales that will produce ephippia and it doesn't affect production nearly as much as a crash.
Actually it can be quite useful to be able to siphon up the ephippia and dry them out as a backup in case the culture ever totally dies off.
The other thing worth remembering is that when you only have a small amount of Moina to begin with you'll have much better results in smaller containers. I started mine in a plastic pint glass and worked up from there as the numbers grew but too few moina in too large of a container is a recipe for disaster as you won't be able to feed enough for them to reproduce whilst also clearing the water before the yeast goes bad.
I'm not sure exactly how yeast actually pollutes the water, whether it's consuming all of the oxygen or whether some other harmful bacteria or fungi begins to feed on the yeast but if you introduce too much at once all of your Moina will begin to cluster at the surface around the edges of the container and once this happens you probably have about half an hour to do a huge water change before there is a mass die off. Similarly if you add more yeast before the water has cleared fully it can very quickly start to smell bad and this is another warning sign of an imminent crash. A healthy Moina culture should just smell slightly earthy when you give it a stir.
 
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Wookii

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It really is a much better solution than yeast but you can also still supplement with a little yeast, paprika, gram flour or whatever else takes your fancy for even more nutrient dense moina.
My bottles are on a pretty much west facing windowsill so they get direct sunlight only in the afternoon and I'm on the west coast of scotland so sunlight is in fairly short supply at the moment. I've also tried them under LED lights and it works just fine but for some reason there seems to be more of an issue with clumping under artificial lights although I've not carried out enough tests to make any seriously valid comparison. Interestingly Chlorella specifically can actually be cultivated in the dark or very low light conditions by adding up to 2 grams per litre of glucose to your culture medium but when grown in this way it tends to be yellow and lacks some of the byproducts of photosynthesis that make it more nutritious. I've also got a bottle supplemented with glucose growing that way and it is indeed yellow but I'm scared to feed it as without a proper microscope I can't actually be sure what it is growing in there and it could easily be some other kind of bacteria.
It looks like you have a different species of Moina to me as my adults are still much smaller than daphnia but noticeably larger relative to a red ramshorn than what's shown in your picture. I think you may have Moina micrura as opposed to Moina macrocopa, I'd happily swap you some Chlorella for a small starter if you're interested. Didn't you say you were thinking of creating a vivarium/paludarium too? I'm about to trim mine so If you're up for a swap I can chuck some Marcgravia trimmings and a baby Priumulinia tamiana in with the chlorella as well.

The were sold to me as Moina macrocopa, but who knows, they could be a different species. To be fair the image I took above (tonight) was taken after 6 consecutive feeds over three days, so many of the largest adults (which seem to hang nearer the surface) have been removed, and there are a tonne of babies in there.

Happy to send you some though - or even a pinch of the eggs if that’s easier.
 

Wookii

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By the way for anyone who can't be bothered with this and just wants to culture Moina with yeast the advice I wish someone had given me before I started was don't worry about underfeeding. If you're anything like me you will crash multiple cultures by either feeding too often, or too much yeast, because you've heard that a lack of food causes them to begin sexual reproduction and Ephippia formation. This is true but it's not remotely a problem compared to a sudden mass die off due to overfeeding. When feeding yeast you really need to make sure that the water is totally crystal clear before you feed again and also that it's only ever slightly cloudy when you do feed, you can put a few leaves or a little bit of hay in the culture as well as some snails to act a a slight buffer for when they clear the water of yeast and even when males do appear it's only ever a few famales that will produce ephippia and it doesn't affect production nearly as much as a crash.
Actually it can be quite useful to be able to siphon up the ephippia and dry them out as a backup in case the culture ever totally dies off.
The other thing worth remembering is that when you only have a small amount of Moina to begin with you'll have much better results in smaller containers. I started mine in a plastic pint glass and worked up from there as the numbers grew but too few moina in too large of a container is a recipe for disaster as you won't be able to feed enough for them to reproduce whilst also clearing the water before the yeast goes bad.
I'm not sure exactly how yeast actually pollutes the water, whether it's consuming all of the oxygen or whether some other harmful bacteria or fungi begins to feed on the yeast but if you introduce too much at once all of your Moina will begin to cluster at the surface around the edges of the container and once this happens you probably have about half an hour to do a huge water change before there is a mass die off. Similarly if you add more yeast before the water has cleared fully it can very quickly start to smell bad and this is another warning sign of an imminent crash. A healthy Moina culture should just smell slightly earthy when you give it a stir.

It’s interesting to read this. Just to give my brief experiences at doing this; before this current culture I’ve failed about 10 times with either the eggs not hatching, or hatching and then dying.

I was advised initially to hatch them only in rainwater, but I couldn’t get a single egg to hatch in rainwater for some reason. So I tried RO with a little potassium carbonate to ensure an alkaline pH, and I got some eggs hatching, but not many.

My next breakthrough was temperature - I found that I got many more eggs hatching if the container was next to a radiator than a windowsill. I also found I got much better hatching in a glass container than a plastic one - I’m not sure why, these were small containers though - around 4 litres.

Whenever I added straw to any of these cultures - either raw straw, or pieces from the compressed pet feed blocks you can buy - the Moina would die off within a couple of days and the water would foul. So I gave up on straw, which was my hope for a long term, low maintenance feeding option.

Out of these 10 failures only one, in the glass container, was a half success - with several generations of Moina. I could only get the numbers to a decent level with consistent feeding every day or two and never letting the water clear. But then I got paranoid of the culture crashing, so I followed the advice as you’ve outlined above, and let the water go gin clear before feeding again, and I got a massive die off of the adult Moina. I fed again, and the young grew bigger, but when I let the water clear a second time they died off too.

I then decided to give it a final proper try before I gave it up as a bad job, and got a larger container (the current 20 litre tank), added a heater to ensure consistent temperature, added an airline to give some water movement past the heater, and a light over the top as I read Moina production increases with a good light source.

I started the culture in the new tank, and got loads of Moina hatch. I added yeast to start it off with and then let the water completely clear again. All the adult Moina died again, though there were a number of babies left.

I’m fairly convinced that I was under feeding, and letting the water completely clear was causing the older Moina to starve?

So I searched the internet and found this document:

CIR1054/FA024: Culture Techniques of Moina : The Ideal Daphnia for Feeding Freshwater Fish Fry

Though it identifies chicken manure as the best feed for Moina commercially, it gives a list of other culture foods and specific quantities per volume.

I used the instructions to make up a 5 day mix in a dosing bottle that I keep in the fridge, but my current dose is essentially 0.3 grams yeast and 0.15 grams of Chlorella (dried) per feed. Those measures are conveniently approximately one ‘smidgen’ measuring spoon per 0.15 grams so I don’t have to get the scales out every time. I add five lots of that to the bottle and mix with warm water.

I started dosing that daily and the population has just exploded.

I’m only about a week or so into this feeding regime, so I could be days away from a crash for all I know. I could also be completely wrong about the adults starving when letting the water go completely clear, but it’s happened enough times on me now to appear to be a pattern, and feeding more heavily has delivered the opposite result, but I can’t be sure.

The reproduction rate of these creatures is incredible though. That 20 litre container is currently producing enough animals for one good feed a day, for two tanks (60L and 100L), at a guess maybe 5-6 days a week. I’ve even had to stop hatching BBS so I can use the Moina up and keep the population in check.

The fish in my two tanks go absolutely crazy for them, even more than they do for the BBS. Even in my low tech, the Pygmy Cories - which are usually very shy, and typically timidly sneak out at feeding time to grab a morsel - all rush out now on-mass as soon as the Moina are added. I don’t know if it’s the erratic movement of the Moina that stimulate a more frenzied feeding response or what!?

I also like the fact that one scoop of the brine shrimp net results in a variety of different sized Moina, so the Chilli’s can hunt the smaller juveniles, and my Embers and Kubotai can hunt the adults. The Moina also appear to actively avoid capture, swimming away surprisingly fast when a fish approaches (poor things lol) which seems to trigger a more natural hunting response in the fish, rather then supping up the BBS or falling granules.

Anyway, sorry for the ‘War and Peace’ length of post, but I’ve been wanting to discuss all these points for a while and this seems the perfect thread 👍🏻
 
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louis_last

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It’s interesting to read this. Just to give my brief experiences at doing this; before this current culture I’ve failed about 10 times with either the eggs not hatching, or hatching and then dying.

I was advised initially to hatch them only in rainwater, but I couldn’t get a single egg to hatch in rainwater for some reason. So I tried RO with a little potassium carbonate to ensure an alkaline pH, and I got some eggs hatching, but not many.

My next breakthrough was temperature - I found that I got many more eggs hatching if the container was next to a radiator than a windowsill. I also found I got much better hatching in a glass container than a plastic one - I’m not sure why, these were small containers though - around 4 litres.
I'm going to respond to lots of the points here because it's good to be able to cross reference our experiences. This reflects my own experience regarding temperature - they for sure like it warm. If I get bored enough I'm going to run some experiments with ephippia that I've produced myself to rule out variables like shelf life and adequate storage affecting optimum hatch parameters. So far my understanding is high light for hatching and culture. I've only ever hatched eggs that came in a small bag of sand and grit but I used distilled water from a garage and had a good hatch rate. I use a 24 hour photoperiod under LEDS for eggs and the adults and actually keep the temperature about 22c to SLOW production.
It freaks me out a bit that you've found they won't hatch as well in some plastic containers because it makes perfect sense and I wonder what's leeching out of the plastic, I think I remember seeing something about this in a video from Malaysia too.
Whenever I added straw to any of these cultures - either raw straw, or pieces from the compressed pet feed blocks you can buy - the Moina would die off within a couple of days and the water would foul. So I gave up on straw, which was my hope for a long term, low maintenance feeding option.
I don't know whether for Moina there is a difference between straw and hay but I use what I know as hay although just like yeast it seems quite easy to overfeed. Just a decent pinch in the culture seems to do alright. I set up two plastic pint glasses as an experiement with just a small amount of hay and moina and they were able to produce several generations without any additional feeding or water changes but I let the cultures run until they crashed. In one of them the moina became infected with some kind of fungus or parasite so that they looked hairy or like they had feathers and shortly afterwards the culture crashed but the other one, even after about 25% of the water had evaporated and it was a stinking mess, still had one or two tiny moina swimming about.
This is something I've noticed whenever I crashed a culture - that there usually seems to be one or two freak 'extremophile' moina that manage to survive pretty much whatever you throw at them.
Out of these 10 failures only one, in the glass container, was a half success - with several generations of Moina. I could only get the numbers to a decent level with consistent feeding every day or two and never letting the water clear. But then I got paranoid of the culture crashing, so I followed the advice as you’ve outlined above, and let the water go gin clear before feeding again, and I got a massive die off of the adult Moina. I fed again, and the young grew bigger, but when I let the water clear a second time they died off too.
How long are you letting the water go clear for before they start to die off? I have mine somewhere that I pass by pretty often so I tend to only wait to notice that the water has recently become clear and then add some food. They probably never go more than 12 hours with totally clear water. I also do a big water change once a week or so, if you use a light to attract the moina away you can siphon off a lot with some airline tubing without sucking them up. They get dirty water from changes in my aquarium. I wonder to what extent the differences we're noticing here are a function of temperature or photoperiod and light intensity. Like I said I keep mine at about 22c and with 24 hours of pretty bright LED light. It's a 15w wavepoint LED strip and I keep the moina in a large flat container with the led sat on top so it's really very bright light, as a result the floor and sides of the container are covered in algae - maybe this is acting as refuge for microorganisms that then work as a buffer when the moina run out of yeast?
I then decided to give it a final proper try before I gave it up as a bad job, and got a larger container (the current 20 litre tank), added a heater to ensure consistent temperature, added an airline to give some water movement past the heater, and a light over the top as I read Moina production increases with a good light source.

I started the culture in the new tank, and got loads of Moina hatch. I added yeast to start it off with and then let the water completely clear again. All the adult Moina died again, though there were a number of babies left.

I’m fairly convinced that I was under feeding, and letting the water completely clear was causing the older Moina to starve?

So I searched the internet and found this document:

CIR1054/FA024: Culture Techniques of Moina : The Ideal Daphnia for Feeding Freshwater Fish Fry

Though it identifies chicken manure as the best feed for Moina commercially, it gives a list of other culture foods and specific quantities per volume.

I used the instructions to make up a 5 day mix in a dosing bottle that I keep in the fridge, but my current dose is essentially 0.3 grams yeast and 0.15 grams of Chlorella (dried) per feed. Those measures are conveniently approximately one ‘smidgen’ measuring spoon per 0.15 grams so I don’t have to get the scales out every time. I add five lots of that to the bottle and mix with warm water.

I started dosing that daily and the population has just exploded.

I’m only about a week or so into this feeding regime, so I could be days away from a crash for all I know. I could also be completely wrong about the adults starving when letting the water go completely clear, but it’s happened enough times on me now to appear to be a pattern, and feeding more heavily has delivered the opposite result, but I can’t be sure.
I've not tried chicken manure in small containers but a couple of years ago I had the moina in a large plastic half barrel in the garden during the summer with about a baseball sized ball of chicken manure and some hay and it was absurdly productive.
I would be very curious to know how feeding live chlorella would work for you and how it compares to the premixed powdered diet. I wonder whether some of your troubles getting cultures initiated were due to using fairly large and sterile containers right off the bat. It seems likely to me that the layer of microorganisms in established biofilm maybe offers some benefit to the moina. I always started them in pint glasses but the final large container I moved them into was 'dirty' with biofilm before I even added the moina.
The reproduction rate of these creatures is incredible though. That 20 litre container is currently producing enough animals for one good feed a day, for two tanks (60L and 100L), at a guess maybe 5-6 days a week. I’ve even had to stop hatching BBS so I can use the Moina up and keep the population in check.
It's amazing right? I don't understand why it's taken so long for them to make their way over here from Asia, a few years ago they were almost impossible to source in the UK. I have mine in a roughly ten litre container and I harvest a small amount once a day to feed a ten gallon tank.
The fish in my two tanks go absolutely crazy for them, even more than they do for the BBS. Even in my low tech, the Pygmy Cories - which are usually very shy, and typically timidly sneak out at feeding time to grab a morsel - all rush out now on-mass as soon as the Moina are added. I don’t know if it’s the erratic movement of the Moina that stimulate a more frenzied feeding response or what!?

I also like the fact that one scoop of the brine shrimp net results in a variety of different sized Moina, so the Chilli’s can hunt the smaller juveniles, and my Embers and Kubotai can hunt the adults. The Moina also appear to actively avoid capture, swimming away surprisingly fast when a fish approaches (poor things lol) which seems to trigger a more natural hunting response in the fish, rather then supping up the BBS or falling granules.
I only feed them to Boraras maculatus and I've also noticed that the frenzied swimming the moina do to try and escape only seems to drive the predators into more of a frenzy. I crudely grade the moina using a plankton seize by placing it in the water and then shining a torch on it, only the smaller moina can swim through towards the light then I suck them up with a pipette.
Anyway, sorry for the ‘War and Peace’ length of post, but I’ve been wanting to discuss all these points for a while and this seems the perfect thread 👍🏻
Don't be sorry, I'm really interested in other peoples experiences. I found a lot of useful information in this thread at the Parosphromenus breeding project especially with regards to feeding live chlorella.

There are some other really cool tiny daphnids that I'm trying to get going now too, Ceriodaphnia dubia and Chydorus sphaericus/ovularis. Both are even smaller than the moina and are produced commercially for fish farms and environmental monitoring. Neither are nearly as prolific as the moina but I'm hoping I might get better results feeding the live chlorella now.
 

Wookii

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Messages
2,360
Location
Nottingham
I'm going to respond to lots of the points here because it's good to be able to cross reference our experiences. This reflects my own experience regarding temperature - they for sure like it warm. If I get bored enough I'm going to run some experiments with ephippia that I've produced myself to rule out variables like shelf life and adequate storage affecting optimum hatch parameters. So far my understanding is high light for hatching and culture. I've only ever hatched eggs that came in a small bag of sand and grit but I used distilled water from a garage and had a good hatch rate.

I use a 24 hour photoperiod under LEDS for eggs and the adults and actually keep the temperature about 22c to SLOW production.

I’m trying to split the discussion points up a bit.

On the lighting, I agree I think a bright light is the way to go. I started off with a little USB powered desk lamp, and it didn’t seem enough, so I added an additional LED strip light, and that was an improvement. You can kind of tell if there is enough light by how high in the water column the Moina hang. I still don’t think I’ve got quite enough light for the whole tank, so I may have to pick up a cheap dedicated aquarium light.

It’s interesting that you run a 24 hour photo period - I’m currently running 16 hours. I have no rational for that beyond the fact that commercial culturing appear to mainly use daylight. Have you found that a 24 hour photo period increases production?

It freaks me out a bit that you've found they won't hatch as well in some plastic containers because it makes perfect sense and I wonder what's leeching out of the plastic, I think I remember seeing something about this in a video from Malaysia too.

Don’t take it as gospel, it was just a brief observation. The plastic containers I used were supposed to be BPA free food storage containers. I just assumed that the glass container somehow improved temperature regulation or light transmission - these containers had no direct lighting or heating.

I don't know whether for Moina there is a difference between straw and hay but I use what I know as hay although just like yeast it seems quite easy to overfeed. Just a decent pinch in the culture seems to do alright. I set up two plastic pint glasses as an experiement with just a small amount of hay and moina and they were able to produce several generations without any additional feeding or water changes but I let the cultures run until they crashed. In one of them the moina became infected with some kind of fungus or parasite so that they looked hairy or like they had feathers and shortly afterwards the culture crashed but the other one, even after about 25% of the water had evaporated and it was a stinking mess, still had one or two tiny moina swimming about.

That is interesting. I don’t know why I had no success with the straw.

I’ve seen some videos of commercial daphnia production they literally use cow manure broken up by hand (🤢) and added as a slurry to massive 1ft deep containers as a substrate - and that produced kilos of daphnia.

When I have emptied my container with the decomposing hay in they’ve very much smelt of manure too strangely.

A long term automated feed seems the ideal solution - so it’s probably worth experimenting. You can buy small bags of chicken manure on Amazon, so I did wonder about trying some of that is a small mesh bag as a longer term feed - depending on how much odour it generates?

This is something I've noticed whenever I crashed a culture - that there usually seems to be one or two freak 'extremophile' moina that manage to survive pretty much whatever you throw at them.

How long are you letting the water go clear for before they start to die off? I have mine somewhere that I pass by pretty often so I tend to only wait to notice that the water has recently become clear and then add some food. They probably never go more than 12 hours with totally clear water. I also do a big water change once a week or so, if you use a light to attract the moina away you can siphon off a lot with some airline tubing without sucking them up. They get dirty water from changes in my aquarium.

I’m not sure - I guess I was leaving the water clear for about a day, and feeding the next day.

I get a fair bit of evaporation out of my tank as it’s running at 25 degrees. So I siphon out about 2 litres (10%) a week, sucking up the fluffy mulm and snail turd that collects on the bottom, and then I add 4 litres of RO back in to bring the level back up.

I wonder to what extent the differences we're noticing here are a function of temperature or photoperiod and light intensity. Like I said I keep mine at about 22c and with 24 hours of pretty bright LED light. It's a 15w wavepoint LED strip and I keep the moina in a large flat container with the led sat on top so it's really very bright light, as a result the floor and sides of the container are covered in algae - maybe this is acting as refuge for microorganisms that then work as a buffer when the moina run out of yeast?

I suspect that could be a strong possibility. When my containers have run clear, they’ve been ‘clean’ containers - with nothing on the walls.

I can imagine if you’ve got a very matured container with lots of algae and other microorganisms naturally occurring, it might help sustain the Moina through the famine period?

Likewise as you say, temperature and light could be factors also - although when I had losses in the other containers, they weren’t heated.

The reality is there are probably too many variables to be sure, but I think we are diverging to a set of working parameters, which might form the basis for others to follow if they choose.

I've not tried chicken manure in small containers but a couple of years ago I had the moina in a large plastic half barrel in the garden during the summer with about a baseball sized ball of chicken manure and some hay and it was absurdly productive.

I do think it’s worth trying. Getting the amount of manure correct, and knowing when to change it out will be key I should think.

How was the smell when you used it in your outside barrel?

I
would be very curious to know how feeding live chlorella would work for you and how it compares to the premixed powdered diet.

I’m keen to give it a go - I have a spare 4 litre container and a light, plus a spare air pump outlet, ready to culture.

Drop me a PM and we can discuss doing a swap - I can send you a pinch of the eggs I have.

I wonder whether some of your troubles getting cultures initiated were due to using fairly large and sterile containers right off the bat. It seems likely to me that the layer of microorganisms in established biofilm maybe offers some benefit to the moina. I always started them in pint glasses but the final large container I moved them into was 'dirty' with biofilm before I even added the moina.

I’m sure you are likely right - an active biooogical ‘soup’ is going to be a better starting place than a brand new sterile one. That said though, my current tank seems to have done well, and that was set up from scratch.

It’s also probably worth me pointing out that I did use two different sources for the eggs/cysts. The eggs from all my initial failures were from a UK based seller.

My more recent success was from using cysts from a US seller - so a different batch. It could well be a quality difference between the two that was a factor?

It's amazing right? I don't understand why it's taken so long for them to make their way over here from Asia, a few years ago they were almost impossible to source in the UK. I have mine in a roughly ten litre container and I harvest a small amount once a day to feed a ten gallon tank.

I only feed them to Boraras maculatus and I've also noticed that the frenzied swimming the moina do to try and escape only seems to drive the predators into more of a frenzy. I crudely grade the moina using a plankton seize by placing it in the water and then shining a torch on it, only the smaller moina can swim through towards the light then I suck them up with a pipette.

That’s a good technique for grading - I’ll remember that one.

I use a brine shrimp sieve and just try and scoop it through the water, but I could do with a proper brine shrimp net (the rigid mesh type netting) with a decent handle, which would be somewhat easier to use.

Don't be sorry, I'm really interested in other peoples experiences. I found a lot of useful information in this thread at the Parosphromenus breeding project especially with regards to feeding live chlorella.

There are some other really cool tiny daphnids that I'm trying to get going now too, Ceriodaphnia dubia and Chydorus sphaericus/ovularis. Both are even smaller than the moina and are produced commercially for fish farms and environmental monitoring. Neither are nearly as prolific as the moina but I'm hoping I might get better results feeding the live chlorella now.

I’d be interested to see what you come up with here. The biggest adult Moina are just on the verge of being a little too large for all but the largest Embers and Kubotai - so an option for something that stays a touch smaller would be good to have if you can get decent production rates from them.
 

jaypeecee

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...probably so few free floating cells of Chlorella remaining that the risk really is minimal and on a par with introducing anything new to your tank that might be contaminated with single celled algae.
Hi @louis_last

Yes, what you have said seems entirely reasonable. And nothing that a UV-C sterilizer wouldn't deal with! That's one of the reasons I like UV-C sterilization - switch it ON or OFF as the situation dictates. And no need for algaecides.

JPC
 
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louis_last

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I’m trying to split the discussion points up a bit.

On the lighting, I agree I think a bright light is the way to go. I started off with a little USB powered desk lamp, and it didn’t seem enough, so I added an additional LED strip light, and that was an improvement. You can kind of tell if there is enough light by how high in the water column the Moina hang. I still don’t think I’ve got quite enough light for the whole tank, so I may have to pick up a cheap dedicated aquarium light.

It’s interesting that you run a 24 hour photo period - I’m currently running 16 hours. I have no rational for that beyond the fact that commercial culturing appear to mainly use daylight. Have you found that a 24 hour photo period increases production?
I only run 24 hours because I read a paper that very specifically claimed they were most productive under 24 hours of lighting. I don't imagine the difference between 16 and 24 hours makes much difference to production though but I also have some small cultures of very rare moss and liverworts under the same light so it kills two birds with one stone. I've never tried any other photoperiod to make a useful comparison.
Don’t take it as gospel, it was just a brief observation. The plastic containers I used were supposed to be BPA free food storage containers. I just assumed that the glass container somehow improved temperature regulation or light transmission - these containers had no direct lighting or heating.
I think it was actually a video from a betta breeder where they said that glass containers worked much better for paramecium. If I was trying to hatch eggs again I would use glass. Some cladocerans (ceriodaphnia dubia) are sensitive enough to certain types of pollution that they're used for environmental monitoring.
That is interesting. I don’t know why I had no success with the straw.

I’ve seen some videos of commercial daphnia production they literally use cow manure broken up by hand (🤢) and added as a slurry to massive 1ft deep containers as a substrate - and that produced kilos of daphnia.

When I have emptied my container with the decomposing hay in they’ve very much smelt of manure too strangely.

A long term automated feed seems the ideal solution - so it’s probably worth experimenting. You can buy small bags of chicken manure on Amazon, so I did wonder about trying some of that is a small mesh bag as a longer term feed - depending on how much odour it generates?
I used totally fresh chicken manure and outdoors the barrel never smelled at all unless you stirred up the muck at the bottom a lot but I think indoors it would absolutely reek. The dried chicken manure pellets might be a slightly different story. I could see them acting a bit like hobby protogen pellets. I might do some comparisons on the window sill with pint glasses - One with a pellet of chicken manure, one with some hay, one with chlorella etc. and let them all run for a couple of weeks with the same number of adult moina added to each initially.
I also fed that barrel freshly cut grass sometimes and that seemed to work well too. I think in larger outdoor systems you probably do still get population explosions and crashes - it's just that there are so many moina that you don't necessarily notice and then the next time it rains the water clears up and they get started again.
I’m not sure - I guess I was leaving the water clear for about a day, and feeding the next day.

I get a fair bit of evaporation out of my tank as it’s running at 25 degrees. So I siphon out about 2 litres (10%) a week, sucking up the fluffy mulm and snail turd that collects on the bottom, and then I add 4 litres of RO back in to bring the level back up.
I'm pretty religious about the 50% water changes each week but I generally leave the snail poo alone on the assumption that it promotes algae and infusoria growth.
I'm also curious whether all snails are equal in this regard, people seem to talk about apple snails as being 'infusorial snails'.
"I put down my success raising pygmy corydoras fry to my use of apple snails. Other members of our local club have had these diminutive cory's spawn and the eggs hatch, but then the fry have died a few days after absorbing their yolk sac - leading to the believe that they starved due to a lack of approriate (sized?) food. It should be noted that these people have rather clean breeding tanks, without apple snails. The only significant difference I can spot between their unsuccessful setups and my successful setup is that I had a couple of apple snails present that had caused the buildup of about half an inch of snail sediment (full of infusoria) - with all of this microscopic food available they were able to get past the critical phase and begin taking larger fry foods such as microworms
I also raise corys and applesnails hatchlings togethor. I hope this is of some interest to you."

I suspect that could be a strong possibility. When my containers have run clear, they’ve been ‘clean’ containers - with nothing on the walls.

I can imagine if you’ve got a very matured container with lots of algae and other microorganisms naturally occurring, it might help sustain the Moina through the famine period?

Likewise as you say, temperature and light could be factors also - although when I had losses in the other containers, they weren’t heated.

The reality is there are probably too many variables to be sure, but I think we are diverging to a set of working parameters, which might form the basis for others to follow if they choose.



I do think it’s worth trying. Getting the amount of manure correct, and knowing when to change it out will be key I should think.

How was the smell when you used it in your outside barrel?
I think there's real potential for great results using both live chlorella and a small amount of chicken manure in the main moina container, seems like the chicken manure would both promote other microorganisms for the moina to feed on and also encourage the alage to continue growing even as it's eaten by the moina. Likewise the algae should remove some of the pollution from the chicken manure. I think this is basically what's happening in the large outdoor manure systems you described for daphnia.
I

I’m keen to give it a go - I have a spare 4 litre container and a light, plus a spare air pump outlet, ready to culture.

Drop me a PM and we can discuss doing a swap - I can send you a pinch of the eggs I have.
will do.
I’m sure you are likely right - an active biooogical ‘soup’ is going to be a better starting place than a brand new sterile one. That said though, my current tank seems to have done well, and that was set up from scratch.

It’s also probably worth me pointing out that I did use two different sources for the eggs/cysts. The eggs from all my initial failures were from a UK based seller.

My more recent success was from using cysts from a US seller - so a different batch. It could well be a quality difference between the two that was a factor?
When I hatched them from eggs it was actually a sachet of Triops eggs I bought in germany that just happened to also hatch a lot of moina.
I’d be interested to see what you come up with here. The biggest adult Moina are just on the verge of being a little too large for all but the largest Embers and Kubotai - so an option for something that stays a touch smaller would be good to have if you can get decent production rates from them.
I don't have particularly high hopes for the Ceriodaphnia dubia ever being that productive, I've got them reproducing but it just doesn't happen at the same rate. I'm trying to breed my boraras maculatus so they might be useful if I get a small amount of fry but not at any sort of scale. They're cultured for environmental monitoring though so I'm trying to find some papers dealing with culturing them.
 

louis_last

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I’d be interested to see what you come up with here. The biggest adult Moina are just on the verge of being a little too large for all but the largest Embers and Kubotai - so an option for something that stays a touch smaller would be good to have if you can get decent production rates from them.

What we need to get our hands on is Moina micrura rather than macrocopa. These are much smaller still. I'm in contact with someone who claims to have them, I'm going to get some and we'll see. I will spread them about if they are the real deal.
 

jaypeecee

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I don't have particularly high hopes for the Ceriodaphnia dubia ever being that productive, I've got them reproducing but it just doesn't happen at the same rate. I'm trying to breed my boraras maculatus so they might be useful if I get a small amount of fry but not at any sort of scale. They're cultured for environmental monitoring though so I'm trying to find some papers dealing with culturing them.
Hi @louis_last

There is a Daphnia Research Group at the University of Reading. I have some of their papers. For more information, this is a good starting point:


JPC
 

jaypeecee

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Hi again, @louis_last

When I once bred German Blue Rams, I used Paramecium caudatum to feed the fry. It was very successful. GBR fry have notoriously small mouths.

JPC
 

louis_last

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Hi again, @louis_last

When I once bred German Blue Rams, I used Paramecium caudatum to feed the fry. It was very successful. GBR fry have notoriously small mouths.

JPC
The experimental culture of ceriodaphnia dubia has had an explosion of what looks like Paramecium since I started feeding live chlorella. It would make much more sense for the invasive organism to be rotifers but it really looks like Paramecium to me. Anyway here's a video for anyone curious about the Ceriodaphnia dubia, the presence of the almost microscopic rotifers/paramecium gives you a good sense of scale - these are mostly adult C. dubia that genuinely reach a maximum size of about 1mm. Best watched in HD.
 
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