Hmmm....we clean it out regularly. It's a 55 gallon.. We've got the 5 parrot fish, 3 silver dollars, 1 platty, 5 of the corrydorras (sp?) 2 small sharks and one of the big sucker fish, 1 paradise fish (she's kinda like a cichlid, but she's super sweet, we've had her for like 2 years) and 2 rope fish..and another kind of fish..she favors the parrots a lot, but she's a different kind..can't remember what she's called for sure....all of our fish seem to get along really great and nobody ever bites anyone... actually tho our tank could probably use some fresh water about now. I'll add some tonight.