Hello, the problem i am having is all my fish are staying up at the top of the tank. it looks like they are trying to breath above water. this has been happening for about 1 mouth. the tank has been set up for 2 mouths give or tank. also in this time i have lost 3 gupies. 2 dawrf frogs. what am i doing wrong? i have a 55g tank set up. cant remeber the name of my filter but its a canister filter made for up to 180g. so i do over filter. my water temp is at about 78. my ph is 7.4. my ammonia, nitrite and nitrate levels are all 0. i have 2 angle fish. 1 ele. 1 cat fish. 2 neon fish. and 3 gupies