I really don't think it should matter how many fish I have in the tank, it doesn't look overcrowded to me. I mean you go to a local fish store and they have plenty of grown cichlids in a tank crowded together and the water is crystal clear. I do agree with you though my goldfish are getting to be beasts and are really messy, two of them are probably 8-9 inches my oscar is full grown, my shovelnose is 21 inches, my plecos are 14-16 inches, the parrots are probably about the size of softballs. The thing is the water hasn't always been like this besides the past month... so I really don't know I guess I'm going to have to do some experimenting with a sterilizer and then a diatom type filter.