I have a 57 gallon with 1 clown, 1 banggai cardinal, 1 mystery wrasse, 1 midas blenny, 1 scooter blenny, 1 hawkfish and one possum wrasse. I have a really peaceful reef but wanted to add another fish to finish the list off and was thinking about adding a damsel. I would like to get a couple but read they will kill each other off until only one is left. What would be the best selection of damsel for semi-peacefulness and coloration? Is this a good fish choice?