I currently have 2 Caribe (5-6 inches)and 2 RBP (6-7 inches) in a 125, and planning to put 10-12 Caribe babies in my open 220 (I was originally going to get a wolf fish but that is slowing in favor of a shoal of Caribe) knowing that I'll end up with 8-10 of the strongest later. The pecking order of the tank is the biggest Caribe-->Biggest RBP--> Caribe-->RBP, tho the smallest Caribe is constantly testing the pecking order.