I have 1 coral beauty,2 longnose butterfly, 1 hippo tang, 2 percula clowns, 1 mandarin goby, and 1 royal gramma. I know that this many fish requires a large tank - I have them in a 55 gal, with a 120 gal being set up now. The thing is, they've been fine for a year together - I have never had a...