I think it depends on the individual fishes. At a place I used to work we had a 12" Volitans in with a full grown maroon, a Niger trigger, Yellow Tang, Purple Tang, Regal Tang, Naso Tang, Foxface, SFE, and Dog Faced Puffer. The lion didn't eat the Maroon and the Trigger didn't pick on the lion but, the maroon did eventually harass the Naso to death. The Naso was very shy and not a good eater though. Other than that one death, everybody got along peacefully.