I have one fry who is smaller then the rest and one day the window was left open making the room about 30 degrees while the tank stayed near 80 degrees I came back after a few hours and the fry had been sitting on the bottom all gasping and having problems swimming up and staying buoyant. A week later all but one now are fine but this little bugger as sad as it is, is my favorite and I have him floating in a container near the surface now. He still sits on the bottom and has a hard time getting to the surface, he also wont go exploring for food anymore. He will eat like crazy if I put the micro worms infront of him but that about it, he's got rapid gill movement and has a hard time staying upright, I added a little epsom salt to see if it would help but no avail (about 1/2 tsp per gallon) also covered his container to try to keep it humid. The older bigger fry are fine but I really want to help this boy. Got any ideas?