One out of my two Rhino Fish the smallest one on his right side part of his Gil broke off and the top is hanging out sometimes it goes back in at a time is it possible have no idea how this happened as there's no other injury to be seen on the outside he still eats but eats a little less has good color and still swims around has anybody have a clue of what might have happened parasite or otherwise...he is house with another rhino that is a few inches larger and a 10" black volt lionfish and a pale noise moray eel