3 of my adults (one went to Paradox) have what I am calling face burn. It appears that they have lost flesh on the upper arms where they usually rub against the aquarium glass. I have never seen this before, and its odd to have 3 have it this time. It doesn't seem to have anything to do with the size of the divided aquarium they are in - the one in the smallest division is perfectly fine. It looks pretty gruesome, but doesn't seem to effect them much. It seems neither to be healing nor getting worse.