: ??? :Can someone please help me? I am new and made the mistake of going to the mall and doing no research on keeping fish. I set up my tank and made lots of mistakes(didn't even clean the gravel just added). I still have all my fish alive though. I have been reading about overcrowding the tank and I need to know if I have. I have a ten gallon tank with 2 fancy guppies, 2 cory catfish, 4 dwarf african frogs, and one pleco algea eater. My concern is the algea eater. I have read that they get really large. Is he too big to keep in my tank? Will having him in there kill my other fish? I have had the tank for 3 1/2 weeks and it is still cycling (I did add the stuff for new tank sydrome), but my nitrite levels are high. The thing that I thing has kept my fish alive is the fact that I bought (unknowingly) a bio wheel filter that is designed for a 25-40 gallon tank. Can someone please help? I have had no fish or frog dealth so far and I really hope I don't have to. Thanks!