The problem with pacus (other than size) is they are playful. They aren't agressive, but sometimes they don't know their own strength. A few weeks ago, one of my pacus decided to play with my florida gar. Pacu grabbed it by the snout and broke it's jaw in three places. Can't be mad at the pacu for it, it's just how they are . They will also make toys out of heaters, filter tubes, pond liners, etc (the way a dog will make a toy out of anything it can get in it's mouth). They are awesome fish, though. Just be careful when deciding what to put with it.