I have a 17"+ true Black Pacu (Colossoma macropomum) up for trade ... not your average red belly variety. Needless to say, they get HUGE ! C. macropomum is the largest Pacu, reaching a length of 5 feet under the right conditions. Large aquariums of 500 gallons or more may be required to hold such a monster fish. Compatible with all fish except those that can fit in their mouths. PM me if you're interested.