I currently have a 55g tank with 3 fish. they are all only 1-2" (flowerhorn, texas, and a red pike). I am using the tank as a grow-out tank till whenever it will be necessary to upgrade them to a bigger one. Does anyone think I will need a canister filter for greater filtration right now, or is that something I could wait on given their size? I am assuming that they are expelling minimal ammonia and nitrate levels into the tank. Right now I just have a standard h.o.b. filter that meets 55 gallon filtration. Please let me know. I want to have happy fish, clean water, and great fishy growth! Thanks!