As the title says, something is wrong with my fish. Or actually, just one of them. The last couple of days, it's been staying stationary around the heater. I didn't get worried until this morning when I woke up and saw it sitting on the bottom of my tank. At first I thought it was dead, then I saw it moving. Now, it's sitting still for awhile (like, no motion at all) then it will swim around the bottom or middle of the tank before settling on the floor again. This one is a Glofish, but the other Glofish and three Zebra danios are doing fine. Swimming around, chasing each other, ETC. The only other occupants of the tank are a couple of Java Ferns and some Wisteria. Oh, and the ever present pond snails. I had one Glofish die last week, but I don't know how either. Woke up to find it on the filter stem. Water parameters are: Ammonia: 0 Nitrite: 0 Nitrate: 10 I'm at a loss here. :;dk Physically, it looks just the same as when I brought it home four months ago. No white spots, no injury's. Nothing. The other fish are happy. I kind of thought it had velvet, but my water is usually warmer than colder, and the only gold color on it are the stripes it had when it came home (both pink fish had them). I'll get a picture up as soon as I can. Thanks in advance.