I have 3 large and 4 smaller in 150gal. The 3 large squabble just about constantly but nothing serious and have settled down a bit. Helped that feeding time more regular now.
Finally the tank plants are growing out so there is a bit of cover for them each.
I think there is just enough tank size that a fish can be 'chased off' for a few feet and then duck into cover.
Fine with anything over neon tetra size. Yo yo loaches harass them. Barbs and mollies run over the top of them to get to food. But every so often an angle fish will hang under a molly clearly pondering how to get a large fish into a small mouth.