My yellow lab started developing a white growth on its right pectoral fin. When i first noticed it was small and seems to be getting bigger. this is the only spot it has and all the other fish do not have them. None of the fish are flashing. my water parameters are good, 0 amonia, 0 nitrite, 10 nitrate. I do 40% weekly water changes, i just got finished doing one, and im going to start the heat and salt treatment just in case, i cant get a good pic of it but its the size of a grain of salt. if anyone can possibly identify, with recomended treatment, preferably a mod.but any help will be appriciated thx.