I ordered 7 for my 5 foot, 115 gallon display. There has been very little aggression. They haven't really been skooling , like I hoped. But I think once my blue throat trigger fish stops hiding and starts swimming around actively.....They should group together more from what i've read. I was really surprised at how large they are. I got a good variety of sizes, which I think helps reduced in aggression. I'm very happy with them. They have brought a lot of movement and life into the setup.