Yes, the lump looks just like a lump. There does not seem to be anything around it. The inside of the gills seem to look ok. It does seem like the gill seems folded up or bent forward persay. Also so does the other gill with out the lump. This bump just appeared within the last week. A closer look at it seems that it is attached to the inside of the gill, but when it breaths it looks like it may have grown around in a shape that allows to somewhat close shut. If that is understandable. Water and other fish are all ok. I have had fish with tumors before so I do not want to treat the tank if it is a tumor. I have not seen this before in any fish I have ever had.