BillD

I would definitely not heat them and use the biggest container you have available. Lighting helps with growing green water. I have a garbage can inside I use to keep some usually, as well as I have used a spare tank at times. It can be hit or miss. It seems that if the food supply is insufficient, the culture will sort of go dormant by producing cysts. i don't spend a lot of time or effort on indoor culture, since i have so many for about 6 weeks every spring. I never filter the daphnia container but sometimes I will add a bubbler to keep the surface from scumming over. I have kept some outside over the summer in just a 3 gallon pail, with no care given to them. Hope this is of some help.
OOPs didn't see the date on this.

Hi Bill, RE: Daphnia

I've still got my Daphnia in a fish bowl which I haven't cleaned and they seem to be doing alright. They don't seem to be multiplying though (at any hugely noticable rate, though I do have more than I started with). If I insist on keeping Daphnia indoors, which I do, should they really be kept in a tank with a heater and or filter of some sorts?