Daphnia culture connected to larger system?

[RickyV]

I am going to attempt a daphnia culture soon and have been thinking about the best way to approach it. I have had very succesful cultures outside that I did not touch at all, however they were probably not the most optimal. It sounds like the main killers of daphnia are overfeeding, and unferfeeding? Overfeeding can kill a culture overnight. And it sounds like daphnia blooms are followed by busts because the population did not have enough food to sustain itself.

Some methods involve adding organic material to the culture that provides food for the bacteria/algae that the daphnia consume. I think this may have been why my one culture did so well since it had a bunch of leaf litter at the bottom.

However the thought of not having any filtration does make me feel uneasy. I know it is what works, but surely some level of filtration would help? I was thinking of doing a daphnia culture connected to my pond, maybe another culture connected to my planted tank. I drip water in the culture, enough to WC it once a day(maybe slower?). And have the water overflow back to the pond (micron mesh on overflow). This would keep the water quality high, and reduce the probability of crashing the culture from overfeeding it (I recently did...). I could add some leaf litter to the bottom.

Thoughts on this? Would the water be too clean for the daphninia and thus there may not be enough food for a nice population? My pond looks crystal clear from the top, but if you put a camera in it there is a lot of particulate suspended in the water. Here is the pond and some underwater footage at the end

 

[RickyV]

Just got the daphnia refugium setup. I'm just waiting for my daphnia to arrive now. I'm kind of curious though what size population the pond water could sustain in there without feeding the daphnia (the goldfish/turtles do make a lot of waste). But for now I'll just keep the flow acting as an automatic WC system and feed them daily. Will also setup another more traditional filterless daphnia setup. When it gets too cold maybe an indoor setup with a sump containing lots of bio media but no mechanical filtration 🤔.
Here is a video of setup right now, I just need to get a valve to slow the flow to a drip.

 

[RickyV]

It's been a few weeks running the daphnia refugium and wanted to share an update. Daphnia have been doing very well. I've been feeding them yeast 2-3 times a week, but I wonder if the particles/microorganisms in the pond water may be enough food for them. I may try upgrading them to a trash bin later. Here is a short video of them.

 

[tam]

That's a good looking population. When I kept them in a bucket (literally) outside I just dropped in fresh green raspberry leaves (still green). When the leaves disappeared I added more. The water was generally clear, not green - which is what's usually suggested for cultures. The daphnia disappear over the winter when it cools, so leaves were in season in time with their cycle. They reappeared the following year. It would be interesting to see if it works indoors over winter or would be too warm.

 

[RickyV]

That's a good looking population. When I kept them in a bucket (literally) outside I just dropped in fresh green raspberry leaves (still green). When the leaves disappeared I added more. The water was generally clear, not green - which is what's usually suggested for cultures. The daphnia disappear over the winter when it cools, so leaves were in season in time with their cycle. They reappeared the following year. It would be interesting to see if it works indoors over winter or would be too warm.

That is good to know I was thinking about starting to feed them some grass clippings, lettuce, or anything that will decompose fast to feed them without my intervention. Then the culture would be ultra low maintenance with infrequent feeding, no WC, and hopefully high production. I will probably setup a backup culture in a bucket using the same feeding to compare to this one. I am curious how long they will stay productive considering Texas winters are relatively mild. I do plan on making an indoor culture for the winter.

 

[tam]

Grass can be very lush - high nitrate maybe - it's has a tendency to rot/ferment rapidly - I don't know the scientific process. I'd be a bit worried it may foul the water as it decomposes too fast. Same with lettuce as it's bred to be soft and palatable. You might be better with leaves from plants/trees that have a bit more structure to them so the break down a little more gradually giving you a steady source of food rather than boom and bust - select ones that would be considered animal safe e.g. bramble, apple, beech. It's only a feeling though, definitely something to experiment with.

 

[dw1305]

Hi all,

You might be better with leaves from plants/trees that have a bit more structure to them so the break down a little more gradually giving you a steady source of food rather than boom and bust - select ones that would be considered animal safe e.g. bramble, apple, beech. It's only a feeling though, definitely something to experiment with.

Agreed <"Small Daphnia culture">. "Slower release foods" definitely work <"Feeding daphnia with crushed fish flakes"> to control "boom and bust" <"Results from experimentation with Daphnia Cultures- Alternate Feeding">.

cheers Darrel