I have a blue spot jawfish in my 50 gal lps / softies tank and he lives in this little rock hut we built him and he pokes his head out. Sometimes he gets discoloured on his underside in small patches which we thought was because of him scratching himself on the rocks but this time his entire underside has gone gray. We have a quarantine tank to work with fyi. other fish in the tank include 2 Anthias, chalk bass a couple clowns and a damsel who is relatively calm. As well as a small tang and a couple grammas.