Well, I went to the mall yesterday, went inside the pet store and in one of these tanks, they had a 20 inch Pacu with 4 6+ inch convicts in there. It was a decent sized tank for the convicts, but don't the Pacu need to be in groups? I was wondering why the tank was so dirty, but I just started to come up with so many combinations of fish now. Anyone know why they would have a 20 inch Pacu in with Convicts in the first place?