So this is interesting. I have two dojo loaches and one is large over 6 inches long. A little over a month ago I noticed he had a reddish lump on his side right behind his right gill that was as big as a small marble. I thought it was a tumor or dropsy and that he was a goner. Well I kept my eye on him and over the course of two weeks it was getting smaller until it went it away completely. You can’t even tell it was there at all now. I wish I would have taken a pic but I didn’t. I wonder what it was, anyone have a theory? Maybe a wound that healed?