Yesterday I did a 25% water change after lunch, then I went to work shortly after. When I got home around 9:30 last evening all my little fry, a few platys and a wcmm were just hanging at the surface. I thought something is wrong so I tested my water. Everything was good and PH,KH and GH were the same as always, no fluctuations. So I checked the temp and it was up to 84 (a little high). I have HOB filters and my water level was right up to where the water comes in. So I took out a couple gallons of water to create more agitation. Over the next couple of hours the fish slowly left the top and started roaming the tank. With the warm temp and the high water level do you think that there wasn't enough oxygen? Everyone is fine today. Temp cooled down overnight to 78. I also kept the water level down a bit. :help: