Hey I have a 75Gallon Long with a 5inch Armatus in it (don't worry he'll be going in a bigger tank by December). This guy is vicious but usually hides in a cave and it makes the tank look empty. Is there any mid aquarium swimming fish that I can put in there that will not get eaten and also look "cool" (colors, scary face..anything). Also a fish that can keep up with in size with the Armatus.