I did a water change yesterday and found some amphipods in my rena canister filter (I removed the bio stars and it's just chemical and mechanical filtration). I put them back in the tank. This happens every time I do the filter. Anyway today I was working in my office, where the tank is, I noticed there were little specs like snow in the tank. I also noticed my damsel seemed pretty thrilled and was swimming around eating some of these things. I ran out to do an errand and came back and when I came back the lights had been off for the night. I took a little flashlight & shined it in on the tank - no snow. So are these copepods?