Not really, i think the more the better! I have a about 30 fishes in my tank all different types. Examples: Conspicillatus Angel fish, Banded Angel, Cross Hatch trigger, Sohal tang, Achilles tang, Goldflake Angel, Scribble Angel, Clarion Angel, Black Tang, Griffis Angel, Personifer Angel, Annularis Angel, Emperator, Majestic, Passer Angel, French Angel, Queen Angel, Asfur Angel, Blue Line Angel, Chrysurus Angel, Blue Face angel, Koran angel, ect...... they get along just fine! Eating like pigs! My "fish only" display tank 300 Gallon Envision 1" thick. Not done yet one more fish in the near future to top it all GEM TANG! P.S must have a very powerful skimmer and Denitrator with this much fish. Example: Reeflo Orca 250 skimmer etc...
Vin "Keep On Reefing"