Since the rule is one inch of fish per gallon of water and I want to abide by this what is the best way to go for my 10 gallon tank? Should I get one 10 inch fish, two 5 inch fish, 3 3 inch fish, of 10 1 inch fish? I don't know what to get! I really want an Oscar should I just get one and be done with it? But I also like Cardinal Tetras should I get 8 or 9 of them? HELP!