i had to say clowns just because that is all i have in my tank right now, and they have the best personality. also, they are so hardy. everytime i reach my hand in the tank to pull some algae off of my star polyps, he comes up to my arm. also, when he sees the bright red cyclopeez package, he swims up to the top and pokes his forehead out of the water. i put some food on my finger and he'll eat it right off.