Daphnia Culture Advice

Wookii

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So I have finally received the Moina cysts and hay blocks:

1DDFE3C6-0955-45EA-B6CE-847F60C3F92E.jpeg

Given the size of the blocks, how much should I be adding to a 4 litre container like this?:

447298CC-BBCF-4664-BA1C-EB1EEC284CA0.jpeg


The water is rainwater with a little ferts added, though it’s not greening up very much given the lack of sunlight currently.

Once I add the straw block, how long should I wait before adding the cysts?
 

jameson_uk

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I now have strike one with the wife telling me the study smelt of stagnant water. Luckily it is me who is working in there so I probably have some time before strike two....

This slimy gloop keeps coming back (and is now there to some extent in both containers).

Presumably smelling isn't a good sign?
Seems to be a lot less Daphnia than there was so I am Tempted to chuck these and start again.
 

jameson_uk

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Too much hay is my guess as well. Just net the remaining Daphnia, and start again.
I have done a little experimenting over the weekend and changed some water and also added a tiny air pump with really low flow. This does seem to have cleared what I can see of the gloop and reduced the smell but it is still there.
I am not sure how much has actually survived; there are certainly a few small daphnia in there but all the bigger ones seem to have vanished and I can't see any Copepods (at one point I could see quite a lot). Obviously the bladder snails seem fine and have actually grown a lot bigger than they do in my tanks.

What I am not sure if how much I can net out without taking some of the gunk. I have read differing opinions on whether they are attracted to light or not. I might try sticking a light over the containers and seeing if anything does come to the surface. The other thing I read was about eggs being dormant in the gunk so not entirely sure whether I am better off throwing everything, cleaning up and starting again or keeping some of what has built up. Given the sachets of live daphnia cost
£1.50 at LFS I am tempted to reset everything and this time leave the hay for a while before adding the daphnia?

Other than ease of removing it is there any need to tie the hay up? (Every pic I have seen has it tied up in a nice bundle so I did without really thinking about it) Adding loose bits I guess would form more of a layer on the bottom than tying it up and this probably isn't as good for them as they seem to want to be higher up in the water?
 

jameson_uk

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After peering in for a while I think I may have another vote to restart. An unnatural movement caught my eye whilst I was seeing what if anything has actually survived and then obviously promptly vanished before I could get a picture.
There was something clear / greeny / brown about 10-15mm long and probably only 1-2mm wide on the side of the container. It seemed to attach itself to the container and then straighten out so it was vertical and then launch. It formed a sort of Omega shape then sprang back to being straight (and then vanished).

This is obviously in some murky water, happened in a few seconds and has been observed by a colour blind person so these details may or may not be accurate... (I am guessing green / brown as it was kind of camouflaged)
The movement suggests a leech? (although I didn't see it change width only curl up and propel itself).

Either way I am presuming it is probably not desirable in with daphnia?
 

jameson_uk

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I have removed the hay (which stank) and will get around to sorting things out over the weekend. I did however see the bug again and I guess this isn't a leech but I cannot match it to anything I have seen on line.

It was hanging about mid water (definitely looking predatory) and I am guessing it is some sort of larvae? Gives me the creeps 👾
PXL_20201110_150602033.MP.jpg


 

dw1305

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Hi all,
. I did however see the bug again and I guess this isn't a leech but I cannot match it to anything I have seen on line.

It was hanging about mid water (definitely looking predatory) and I am guessing it is some sort of larvae?
It is a <"Glassworm" (Chaoborus)">, a predatory midge larvae (they actually eat Daphnia). They need quite high quality water, so in some ways it is a positive find.

Fish love them, but they are difficult to culture, so are usually wild caught as by catch with Daphnia.


cheers Darrel
 

jameson_uk

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It is a <"Glassworm" (Chaoborus)">, a predatory midge larvae (they actually eat Daphnia). They need quite high quality water, so in some ways it is a positive find.

Fish love them, but they are difficult to culture, so are usually wild caught as by catch with Daphnia.
Just spotted there are two in there (I guess there are most likely more) and they are real buggers to catch (well using the beaker I had to hand anyway)
Are these likely to have come from the shop bought live daphnia or from the water from bird bath / garden tub? (Just thinking about when I do clean it out a little and add some more daphnia)

David Livingstone (1865) claimed that they "tasted not unlike caviare"
Not sure I fancy trying to eat them.
 

jameson_uk

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Would be my guess.
Not ideal to include a predator with them then!!! Is this common as just thinking about starting up again and if I source daphnia from LFS and it includes glassworm then they are quite hard to spot in green water. Am I better off getting a better source of daphnia or just picking them out if / as I find them?

It was only when I saw the video and then read another article that I realised that they are White Mosquito Larvae. I feed these frozen and fish love them.
try a long plastic pipette for collecting them, used to use that to also separate daphnia out
I have a turkey baster I used to use to remove uneaten food from the shrimp tank so will give that a go.
 

BigD

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Glassworm are easy to spot in a bag of daphnia. Just ask the LFS for a back that does not contain them. There are rarely more than a couple in a bag, so removing the two that you have should be sufficient.
 

Wookii

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So I’m calling my first attempt at hatching the Moina a bust, I can see anything moving in the water column after over a week. This time I’ll leave the hay out until later and start the Moina off with the yeast that came with the starter pack:

AD001DCA-6E15-43F0-BDD5-F66A47A562C6.jpeg


The snails have thrived though, and laid eggs everywhere! Can anyone hazard an ID?:

image.jpg
 

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