Looks like Lymphocystis lesions which are small to medium-sized fibroblast nodules or warts on the fins, skin, or gills of the fish. Although other organs may be infected, growths on the fins, skin, and gills are more common. Because lymphocystis lesions may not always be visible to the naked eye, fish tissues may still need to be examined microscopically. Each infected cell is surrounded by a thick membrane. Fibroblasts are connective tissue cells normally found throughout the body, and so lymphocystis nodules may be seen internally as well as externally. However, fibroblasts in the skin, fins, or gills are more commonly affected.
Most often, the disease must run its course in an affected fish. Fortunately most cases of lymphocystis in warmwater fish will resolve on their own after a few weeks, as long as husbandry is good (good water quality/chemistry, good nutrition, correct population densities, optimal social groups) and as long as other stressors have been eliminated.
