Until I moved them to their new home on 17 March I kept a Magnificent foxface, Yellow foxface, and a common "Squiggle" rabbit, in my 180. In their new home they are joined by a Fiji, Spotted, and another type of rabbit. All six stay together and there is very little aggression between them. They range in size from 1.5 inches (Spotted) to 6+ inches for the Squiggle Rabbit and M Foxface. They all do fine and the magnificent tends to protect the others from the more aggressive tangs. I don't think the Magnificent does it on purpose but he will not allow a tang to act aggressive around him so the other fish would run to him and hide behind him in the smaller tank. In the 325 I have very little aggression as the tank is square and the fish can be out of site of each other . I would not hesitate to put three or more togeterh in a 180 but I wouldnt ry two of them. I find that more is better when dealing with agressive fish.