I've never had a pacu before so this may seem like a no brainer but i don't know much about them. I know they can get really big and i do have a big tank on the way so no need to worry about that. Right now i have 3 of them at 4" a piece and they swim back in forth in there 125 but just the other day i was watching them swim (This was the first day i actually sat down and watched them swim focusing in on them) and they were swimming sideways. Is that normal? They play follow the leader and swim back and forth and they all swim on there side. I thought it might just be from when they're eating but it's all the time. They look healthy. So what's up with them? Is it normal?