What is daphnia?

[tricksterpup]

Matak:
I have heard stories of people building refugiums and keeping daphnia in them. I think i saw something like that at the Krib, but don't quote me on that, some time ago. But if you have an empty tank and lots of green water, you could do that and have tons of live food when you need it.

jim

 

[wetmanNY]

Yes. Absolutely. The problem is that the fish will hunt them down and gobble them up. Some tangles of Java Moss would help. They need a "refugium."

In aquaria with soft acidic water, copepods take the place of daphnia. They aren't as efficient, working as filter-feeding grazers on the green water/cloudy water plankton, though. But smaller critters are also eating greenwater algae, bacteria etc. Rotifers, for instance.

I think a healthy plankton population does more to keep aquarium water clear than any pro-active measures we can take.

 

[Matak]

Originally posted by wetmanNY
In aquaria with soft acidic water, copepods take the place of daphnia.

How about soft neutral water?

Looks like the only way I could keep daphnia in my tank would be to run a sump and keep the critters in the sump. Would it work to keep the daphnia in a fry box or something similar?

 

[RTR]

If you are using them to improve water quality - i.e., a higher-than-bacterial biofilter - the refugium is exactly the concept. I learned this and adopted it originally from Pet Library's "Advanced Aquarist Guide" by Feroze N. Ghadially, 1969. Long out-of-print, but a quite useful technique to me over the years since.

If you are raising the daphnia for food, a separate tank/container (to retain the green water you will be adding) is better IME. Green water I generate by exposed to the water column pieces of Jobes' plant spikes.

 

[Tom.E]

The Hamburg Mattenfilter design looks promising as a refugium. At Tom’s Place http://www.tomgriffin.com there’s a thread in the Aquarium Technology forum and an article in Aquasource about them.

I collect both daphnia and copepods from acidic waters, so if your tank water matches the source it shouldn’t be a problem. What I have noticed is that daphnia populations are stronger during spring/early summer whereas copepods dominate in the late summer/fall. Probably due to the changing plankton composition and predation (fish hatchings, cyclops, insect larvae) throughout the summer.


Tom

 

[RTR]

Tom.E - let us know if you do use the Mattenfilter as refugium. I considered setting shrimp breeders with them, but backed out and am using existing sponge filters.

 

[NJ Devils Fan]

Originally posted by NJ Devils Fan
So I was thinking, maybe I should feed daphnia on like friday to clean the fish out because saturday is my fasting day. What do you think about that?

anyone.....anyone..... bueller.....bueller

 

[Matak]

Originally posted by Dangerdoll
Frozen is the way to go if that's your purpose NJ. I think it's a great idea to use the daphnia to help the clean out process.

 

[NJ Devils Fan]

WOW, didn't even see that.

 

[Tom.E]

RTR- Probably this winter. I’m very interested in seeing how well the organisms in the upper substrate of a tank colonize a maturing Mattenfilter. To me the mat looks like it has excellent potential as a supplementary feeder in a fry or invertebrate set-up.

As for as a refugium, the tank I plan on aging the mat in already has a few hundred daphnia in it. So there will definitely be some daphnia “trapped” between the mat and glass.



Tom