RE: [Killietalk] moina, Japanese daphnia

[Chris <cgraseck at optonline_net>]

I'm in Lees camp.  Daphnia are a good food but getting enough really
small ones is not easy and adding a lot of adults to a fry tank is not a
great idea.  They can be so annoying to the fish that the fish stop
feeding altogether.  They can be sieved but this causes air to get under
many of their shells and then they just float at the surface.

I've had a culture of what looks like D. pulex going for almost a year
now (see my gallery on the AKA site)  I also just recently tried a
culture of Ceriodaphnia.  Believe it or not they crashed due to an algae
bloom!  I don't know if there are any left now.  It's too bad that I
don't have them anymore as they were very small.

As far as feeding them goes, many of the foods Brother Paul mentioned
will probably sink to the bottom before the daphnia eat them. They will
feed on the bacteria bloom that will result from adding those foods
though.  I feed my cultures with powdered tetra bits.  No matter how
fine a powder I make most of it settles on the bottom where the snails
and ostracods feed on it.  The ensuing bacteria bloom is what keeps the
daphnia going.  I also keep a double fluorescent fixture (2X40 watts)
going over the cultures at all times. This helps keep some algae growing
in the cultures.  

Daphnia have strong positive phototaxis so to harvest them I simply turn
the lights out and shine a flashlight into one of their tanks.  They all
come running to the light and then I pipette them out.  I don't rinse
them as this traps air under their shells.  Instead, I add chlorinated
water to the cup that I collect them in and let them sit for a while.
They can be allowed to sit over night at high density without
significant die off.




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