[flamingo]

I would say get rid of it as soon as you can or get a bigger pond than a 300 gallon, a 300 won't even fully cater to it's huge size requirements. Of course, it's better than a 55 but still.....

It could be okay two months, just try not to stress him. When I got my first pacu it grew about a foot and flipped out and smashed it's head into the side of the tank and died. Also, like said, your catfish may be in harm. They are herbivorous creatures but any animal will eat meat if given the chance. Mine used to eat feeders for my other fish in the tank all the time.

Also, he does look good, prolly just a little stressed. What are you feeding it? It's scales are nice, nose doesn't have rub marks... seems fine except the size issue.

Just remember these fish have know to get 36 inches, they never really stop growing. Yours is a black pacu also and they tend to get a little bigger then red bellies.