75% of people tell me 1 inch per gallon.  10% tell me 1 inch per 2 gallons.  10% tell me one fish per 10 gallon tank.  The other 5% seem to say 2 inches per gallon, and change half the water every week.
I like fish.  I dont have any space for a bigger tank, and theyve been doing fine, except that one bastard fish.  I couldnt bear to ummm...thin the ranks in the tank just because theyre supposedly overcrowded.
Besides, the frog always hides, the newt hates the water, and one of the fish is a lesbian.  Dont ask.