Daphnia Culture Advice

MirandaB

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What do the pellets smell of that came with the kit @jameson_uk ?
They might be organic chicken manure pellets...I use those for my outdoor cultures along with green water.
Oddly enough since using that I've not had boom and bust event in any of them.
 

jameson_uk

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What do the pellets smell of that came with the kit @jameson_uk ?
They might be organic chicken manure pellets...I use those for my outdoor cultures along with green water.
Oddly enough since using that I've not had boom and bust event in any of them.
Just got strange looks off the wife for sniffing them

I would describe the smell as a bit like when you go into a barn at a children's farm. A bit grassy mixed with wee.
 

Wookii

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Just got strange looks off the wife for sniffing them

😂😂😂 Brilliant - I’ve got a mental image of you in the corner of your room sniffing the pellets:

1602793618919.gif
 

jameson_uk

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So after adding a bit of the hay and some of the water from the garden there is a pretty thick build up on the surface. Should I skim this off or just leave it?
 
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dw1305

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Hi all,
Should I skim this off or just leave it?
I would probably skim it off with some kitchen towel, just in terms of gas exchange, but my guess is that it won't make much difference.

I use less hay than that (probably about 1/2 as much) but I'm not after very quick population growth. When I'm trying to "breed" mosquitoes in the summer outside I use more grass than that, and those cultures will still support Daphnia.

cheers Darrel
 

jameson_uk

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So there has been a definite lightening of the water which I guess is the contents getting eaten.
The culture on the left seems to be doing pretty well and there are lots of daphnia and they are getting quite large
PXL_20201022_113243005.MP.jpg

PXL_20201022_113220153.MP.jpg

But the one on the right has far fewer daphnia and they are tiny. It is also starting to smell (not sure how I would describe it but is isn't pleasant, sweaty socks?:doctor:) .
Other than changing a bit of water in the right hand container is there anything I ought to do? Might I have introduced some sort of predator from the water sourced from the garden (they both had water from the same source so just seems a bit odd that only one smells). Photos are about the same zoom level and both cultures have basically been given identical care.
PXL_20201022_113228281.MP.jpg
 

dw1305

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Hi all,
far fewer daphnia and they are tiny
They look like a <"Copepod Cyclops">. Fish absolutely love them, but they are more difficult to culture in large amounts.
The culture on the left seems to be doing pretty well and there are lots of daphnia and they are getting quite large
They are doing really well. I'd sub-culture them now.
Other than changing a bit of water in the right hand container is there anything I ought to do?
Add some tap water? You often get a swap from Cladocerans to Copepods as carbonate hardness falls.

cheers Darrel
 

jameson_uk

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They look like a <"Copepod Cyclops">. Fish absolutely love them, but they are more difficult to culture in large amounts.
The larger ones are Daphnia though? Now looking at pictures I can't tell o_O. When they first arrived and were in clear water there was definite jerky movement not I am not seeing much of that now and they seem to be congregating in the corners.
There are most definitively some cyclops in both containers as these are the ones that look (in my head anyway) like space rockets. I wonder whether these came with the daphnia or from outside?


They are doing really well. I'd sub-culture them now.
Any tips to get them out? Just submerge a beaker to suck them in and pour into a new container?
Also order of magnitude are we talking about for how many daphnia should I be expecting in one of these four litre containers?

Add some tap water? You often get a swap from Cladocerans to Copepods as carbonate hardness falls.
Interesting. Whilst my GH is relatively high the KH is only 5. The containers were filled about half full of aquarium water so I guess the KH probably has dropped quite low.
Will have to figure out the opposite of above where I want to take some water out and not the occupants.... I guess I just put everything through the net and put anything that does get caught into the tanks.
 

dw1305

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Hi all,
or from outside?
Probably from outside, I find them in the water butts, blackworm buckets etc. There are always a few, but rarely very many.
Any tips to get them out? Just submerge a beaker to suck them in and pour into a new container?
Beaker will do, or use a net. The numbers will build up again fairly rapidly.
are we talking about for how many daphnia should I be expecting in one of these four litre containers?
I would let them get any denser than they are at the moment in the left container. Population growth is pretty exponential and, in my experience, boom is inevitably followed by bust.
I guess I just put everything through the net and put anything that does get caught into the tanks.
Tip it through a fine net and then just repatriate the inhabitants. I'd be tempted to just replace any evaporation with tap water at the moment. You have a spare culture should anything horrible happen, as I'm not sure about Daphnia and dechlorinators etc.

If you are going for a larger water change I'd let the tap water stand for a couple of days.

If you already have potassium bicarbonate (KHCO3)? you can add a pinch of that.

cheers Darrel
 

jameson_uk

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I would let them get any denser than they are at the moment in the left container. Population growth is pretty exponential and, in my experience, boom is inevitably followed by bust.
Even though this is just one corner of the container? (seems most of the occupants had crammed themselves into about 1% of the container). Just trying to get a feel of when to do it (I haven't actually harvested any for the fish yet)
I will try and get some water in a container with some hay tonight then look at transferring some across over the weekend..
I'd be tempted to just replace any evaporation with tap water at the moment. You have a spare culture should anything horrible happen, as I'm not sure about Daphnia and dechlorinators etc.

If you are going for a larger water change I'd let the tap water stand for a couple of days.

If you already have potassium bicarbonate (KHCO3)? you can add a pinch of that.
I don't have any KHCO3 but I am might as well just use water from my main tank? (the KH never seems to drop much in my main tank)
 

dw1305

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Hi all,
I don't have any KHCO3 but I am might as well just use water from my main tank?
Yes that should be fine, it just needs some dKH.
I haven't actually harvested any for the fish yet
Harvest some every day. If you don't have many, just harvest a few, if you have a lot, harvest more. If number start declining? add some more hay or pellets etc. and then don't harvest again any until you get back to a reasonable population.
Even though this is just one corner of the container?
OK, you are good for a while then. I thought looking at the container (from above) that all the pinky dots were Daphnia.

cheers Darrel
 

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