The tank mates are just a black moor and a fancy goldfish.... Checked waters and all are good... Did find him in filter this morning and think he could possibly be doing it on the filter media as it is a bit raspy... I have slightly lowered water level so he can't keep climbing in. But is they're anything I can put in the water to help him or will he recover on his own? He has also been out and about in the tank more over the last couple of days and he likes the cucumber that was suggested too.