How to: Clean, easy and highly nutritious greenwater culture for Daphnia and Moina.

[Wookii]

@MirandaB @ScareCrow - how are you guys getting on with your Dero worms? I've just ordered a starter culture set to try them out.

With moving house this year, and being so busy, I'm late to the party getting my outdoor Moina tubs going. I'm on my second failed attempt at hatching some cysts. I don't know whether the cysts go out of date (I've had them over a year), or I'm doing something wrong (2 litres of rain water from a butt in a glass vase), but I just can't seem to get any live ones? My outdoor 80 litre tub with an oak leaf substrate is now over ready for them.

This year I need to see if I can maintain a population through the winter so I don't have to go through this PITA hatching process each year.

Also, has anyone got any thoughts on the idea of just chucking some black worms in the outdoor tubs too?

 

[Conort2]

Also, has anyone got any thoughts on the idea of just chucking some black worms in the outdoor tubs too?

I’ve chucked some in with daphnia in a old washing up bowl and they’re doing surprisingly well. It’s in direct sun for most of the day so I thought it’d be too warm but they do fine. No food is added except for some dried beech leaves and the daphnia are booming and have to be harvested constantly.

Can you not just buy some bags of live daphnia to get you started rather than cysts?

Cheers

 

[Wookii]

I’ve chucked some in with daphnia in a old washing up bowl and they’re doing surprisingly well. It’s in direct sun for most of the day so I thought it’d be too warm but they do fine. No food is added except for some dried beech leaves and the daphnia are booming and have to be harvested constantly.

Can you not just buy some bags of live daphnia to get you started rather than cysts?

Cheers

Thanks Conor - no daphnia are generally too large for most of my fish, especially the adults, so they tend to ignore them. Moina are a fair bit smaller and so perfectly sized.

Moina are a lot more resilient and faster breeding that daphnia, and appear to be used extensively in the Asian fish breeding trade, so I'm not sure why they don't exist in the UK trade like daphnia do. Long and short of it though, pouches of live moina don't seem to be available.

 

[dw1305]

Hi all,

Also, has anyone got any thoughts on the idea of just chucking some black worms in the outdoor tubs too?

<"Good idea">

It’s in direct sun for most of the day so I thought it’d be too warm but they do fine. No food is added except for some dried beech leaves and the daphnia are booming and have to be harvested constantly.

Are they very pink?

Can you not just buy some bags of live daphnia to get you started rather than cysts?

Daphnia always end up in the water butts <"without any intervention">, but I'm not sure about Moina.

I'm pretty sure we have some native UK species, I'll see what I can find.

cheers Darrel

 

[Conort2]

Are they very pink?

Just their normal brownish sort of colour, they keep to the beech leaves in the day and then spread around the container once the sun goes down.

 

[Conort2]

Thanks Conor - no daphnia are generally too large for most of my fish, especially the adults, so they tend to ignore them. Moina are a fair bit smaller and so perfectly sized.

I just feed the younger ones to my nano fish and the big breeders either remain or get launched into the big tank every now and then to curb their numbers.

 

[Wookii]

I just feed the younger ones to my nano fish and the big breeders either remain or get launched into the big tank every now and then to curb their numbers.

I might stick some daphnia in one of the tubs then, and see how they go. The chocolate gourami might be able to take adults - I didn't have them last time I tried feeding them.

 

[Conort2]

I might stick some daphnia in one of the tubs then, and see how they go. The chocolate gourami might be able to take adults - I didn't have them last time I tried feeding them.

You’ll be surprised, my tucano tetra and green line pencilfish manage to eat some pretty big ones and their mouths are tiny.

 

[ScareCrow]

@MirandaB @ScareCrow - how are you guys getting on with your Dero worms? I've just ordered a starter culture set to try them out.

With moving house this year, and being so busy, I'm late to the party getting my outdoor Moina tubs going. I'm on my second failed attempt at hatching some cysts. I don't know whether the cysts go out of date (I've had them over a year), or I'm doing something wrong (2 litres of rain water from a butt in a glass vase), but I just can't seem to get any live ones? My outdoor 80 litre tub with an oak leaf substrate is now over ready for them.

This year I need to see if I can maintain a population through the winter so I don't have to go through this PITA hatching process each year.

Also, has anyone got any thoughts on the idea of just chucking some black worms in the outdoor tubs too?

I didn't go for the dero worms in the end. The warning over their smell put me off as I was about to put my house on the market at the time.
With regards to moina, I think they like it warmer than daphnia. I put the tub I was culturing them in, in my garden a couple of months ago and the culture stopped producing. I put it back in my South facing porch a week ago and the population has doubled with just beech leaves, snails and Asellus aquatics providing a food source for the infusoria that then feed the moina. I'm going to add some yeast so I can get a harvestable quantity again.
In my waterbutt I have daphnia, snails, Asellus aquatics and black worms. For whatever reason I don't seem to do well with black worms. They sort of boom and bust but get nowhere near the numbers I've seen some people have before they crash.

 

[Wookii]

So the Dero worm culture arrived. Three decent portions, plus a container, sponge, and some dried oats to feed. I bought two 2 litre jugs, so the three pots of worms worked out well. I put one in each jug 2/3 filled with tap water, and one in the supplied container with the sponge.

I fed some left over worms to the fish to see how they got on with them, it was quite funny to watch. They are completely used to being fed grindal worms which don't move much and slowly sink to the substrate. The dero worms wriggle more, and actually swim up into the water column. The Chocolate Gourami's looked at them like - what the hell are these things doing? - before chowing down on the lot of them!

I also bought some packs of daphnia and black worms off eBay (after not one of my four LFS had any in stock). I put some into two large 80 litre storage tubs that are in the garden with leaf letter and algae in, and some in the water butt on our shed.

Again I kept some of them back to try feeding to the fish. Between the chilli's, ember and Chocolates, they managed to eat almost all the daphnia beside the very largest that even the Chocolates didn't want to tackle, so they were a good shout @Conort2 - easier to source each year than the Moina - hopefully they'll breed up well in the tubs.

If the dero worms were funny to watch being eaten though, the black worms were absolutely hilarious! I've never seen a worm act so erratically when it thinks its being threatened - several times the Chocolates would suck in a worm longer than their body like a giant piece of spaghetti, only for it to completely wriggle back out their mouths and escape again. The Chocolates started stalking the worms slowly working their way around to find a pointy end, and then strike like a cat and suck it up. Brilliant to watch - I'll have to try and film it next time I feed some.

 

[brhau]

Hi all,

I've been trying to reproduce this protocol, and can confirm that the Biobizz Fish Mix is a pretty important component.

On my first try, I used Guillard's f/2 medium. I was able to expand the Chlorella slightly with this, but noticed that the growth stalled out after a few days, and definitely not at saturating concentrations. After some research, I learned that people tend not to use f/2 for freshwater cultures, but rather something more nitrogen rich, like Bold's Basal Medium.

So I got some Bold's Basal Medium (BBM) and Biobizz Fish Mix to try side-by-side. Immediately, I could see that the Fish Mix has molasses in it and is extremely viscous. That says to me right away that there's more food in it, and it won't be much of a competition. The BBM, by contrast, is colorless and transparent at 1X concentration.

Here's a photo of the two cultures (and a cat) after about three days. You can see the culture in BBM is lightly tinted green, but isn't very saturated. That's about as concentrated as it gets without continuing to add concentrate. The Fish Mix media, on the other hand, starts out pretty brown from the molasses. It's not far off from what you see in the photo, except that you can already start to see a green tinge here:

Here are the two jars another 2 days later. The culture in BBM ran out of food and crashed. The culture in Fish Mix has turned dark green and has quite a bit of green sediment. Once the algae have settled, the media is still pretty brown.

My only concern is whether the residual brownness in the media will be an issue with the moina. i.e., Will it eventually decompose and create ammonia? I might try growing the Chlorella at 1/2 the concentration of Fish Mix (1:2000) so that they consume more of the media before I add it to the moina.

Cheers

 

[Wookii]

My only concern is whether the residual brownness in the media will be an issue with the moina. i.e., Will it eventually decompose and create ammonia?

It may do, but the Biobizz Fishmix contains a lot of ammonia already out of the bottle. I had issues feeding the chlorella culture to the moina when there was too much ammonia still in there, and it killed the Moina culture. I tried adding additional micros and PO4 as I suspected that the culture ended up bottoming out one nutrient or another and stalled before all the ammonia had been consumed. I think starting with half the dose originally advised by @louis_last is a good starting point, and even less may be sufficient, and maybe adding a little PO4 and micros half way through the culturing time.

Like you, I tried culturing the chlorella with other fertilizers. I had some success with standard aquarium ferts, with much safer KNO3 as the nitrogen source, but also like you've found, I never got the same chlorella density as with the fish mix.

Eventually I gave up on trying to maintain small indoor cultures of both moina and chlorella, as it was just taking too much 'input' from me. Instead I set up a large (60 litre) clear plastic container in the garden, covered the base with dried leaves (oak and beech), added a solar powered pond airstone and added some moina to that. That worked brilliantly, required no input from me, and was hugely productive.

This year I've done the same again with a newer 80 litre container, oak and beech leaves, but I've not been able to successfully hatch any moina cysts sadly, so I reverted to adding some live daphnia and blackworms as discuss above. That has been very successful so far - the daphnia population has exploded and I'm able to get a large feed out of it every 3 days or so for 60+ fish.

 

[Wookii]

So the Dero worm culture arrived. Three decent portions, plus a container, sponge, and some dried oats to feed. I bought two 2 litre jugs, so the three pots of worms worked out well. I put one in each jug 2/3 filled with tap water, and one in the supplied container with the sponge.

View attachment 190256

I fed some left over worms to the fish to see how they got on with them, it was quite funny to watch. They are completely used to being fed grindal worms which don't move much and slowly sink to the substrate. The dero worms wriggle more, and actually swim up into the water column. The Chocolate Gourami's looked at them like - what the hell are these things doing? - before chowing down on the lot of them!

I also bought some packs of daphnia and black worms off eBay (after not one of my four LFS had any in stock). I put some into two large 80 litre storage tubs that are in the garden with leaf letter and algae in, and some in the water butt on our shed.

Again I kept some of them back to try feeding to the fish. Between the chilli's, ember and Chocolates, they managed to eat almost all the daphnia beside the very largest that even the Chocolates didn't want to tackle, so they were a good shout @Conort2 - easier to source each year than the Moina - hopefully they'll breed up well in the tubs.

If the dero worms were funny to watch being eaten though, the black worms were absolutely hilarious! I've never seen a worm act so erratically when it thinks its being threatened - several times the Chocolates would suck in a worm longer than their body like a giant piece of spaghetti, only for it to completely wriggle back out their mouths and escape again. The Chocolates started stalking the worms slowly working their way around to find a pointy end, and then strike like a cat and suck it up. Brilliant to watch - I'll have to try and film it next time I feed some.

A quick update on these dero worm cultures. The two cultures in the jugs completely died on me. I'm not sure why - they were alright for a week or so with a large water change every few days, fed a some sinking bug bites. They I tried feeding a half a Hikari algae wafer, and two days later they were all dead. Too much food perhaps?

The remaining culture on the sponge seems to be doing OKish - it seem to be growing in numbers and the worms seem to be consuming around 1/4 teaspoon of ground oats in about 2-3 days, but are not yet at the numbers where I can farm any.

Once I have the sponge culture producing I’d like to set up a small 20 litre tank with mature filter, to see if I can culture them easier that way, maybe with daphina and Moina in there too.

 

[castle]

I don’t think it’s quite the same scale, as in I harvest sporadically but I had Moina in a bucket (60l) in the greenhouse which I have fed with straw (non barley) and occasionally some chicken waste.

The only reason I stopped it, was because I found them to not grow too well, and I think that’s because I was quite blasaé with it. I’m unsure they can deal with low evening temps, then 30c in the day.

Having now read through this, I’ll give them another go. It’s really obvious how much better for the fish moina are, colouration and growth is far better than daphnia, but daphnia are far more easier to culture imo 🫣

 

[Wookii]

I just feed the younger ones to my nano fish and the big breeders either remain or get launched into the big tank every now and then to curb their numbers.

@Conort2 do you use some sort of grading net to remove the larger adults from the smaller baby daphnia. At the minute I'm just using a large brine shrimp net to harvest them, and my Chocolate Gourami are able to eat maybe 90% of the daphnia sizes, but the largest 10% get left and I'd rather leave these in the tub to produce more offspring if you have some sort of grading net you can recommend?

 

[Conort2]

@Conort2 do you use some sort of grading net to remove the larger adults from the smaller baby daphnia. At the minute I'm just using a large brine shrimp net to harvest them, and my Chocolate Gourami are able to eat maybe 90% of the daphnia sizes, but the largest 10% get left and I'd rather leave these in the tub to produce more offspring if you have some sort of grading net you can recommend?

I’m not that careful if I’m honest I just try and aim to get the smaller ones. I’ve got corydoras though who can manage the large ones the tetras don’t hoover up. Think the brine shrimp grading sieves should do the trick though if you want to catch a certain size.

I’ve managed to cook my daphnia and blackworm culture in this weather so starting from scratch unfortunately.

 

[Wookii]

I’m not that careful if I’m honest I just try and aim to get the smaller ones. I’ve got corydoras though who can manage the large ones the tetras don’t hoover up. Think the brine shrimp grading sieves should do the trick though if you want to catch a certain size.

Ah OK - I'll have a hunt around for a grading sieve. I guess I need something in the 2-3mm range.

I’ve managed to cook my daphnia and blackworm culture in this weather so starting from scratch unfortunately.

That's a shame - at least they are readily available online.

 

[brhau]

Eventually I gave up on trying to maintain small indoor cultures of both moina and chlorella, as it was just taking too much 'input' from me. Instead I set up a large (60 litre) clear plastic container in the garden, covered the base with dried leaves (oak and beech), added a solar powered pond airstone and added some moina to that. That worked brilliantly, required no input from me, and was hugely productive.

Do you think this is due to having much more light, so you don’t have to worry about culturing chlorella?

 

[Wookii]

Do you think this is due to having much more light, so you don’t have to worry about culturing chlorella?

Probably, but I also think the slow decay of the oak leaves must release food into the water column either directly as organic particles the Moina/Daphnia can feed on , or indirectly by encouraging the populations of bacteria and other microorganisms that they can feed on.

 

[brhau]

Probably, but I also think the slow decay of the oak leaves must release food into the water column either directly as organic particles the Moina/Daphnia can feed on , or indirectly by encouraging the populations of bacteria and other microorganisms that they can feed on.

I have leaf litter in my indoor jars, ready to go. Ostracods have already appeared there. I just haven’t been able to expand the moina after hatching. They live around a week, but haven’t taken off fast enough to transfer them to the larger container. I think partly I might be killing them when adding chlorella/fish mix.