It would be a good idea to try and determine what is causing the clouded eye before you treat it. Fungal infections are very rare in saltwater fish and it usually appears as a white mucous on the skin or fin rot. A parasite is most likey the cause. In any case a fresh water dip is a very effective cure as long as it is done properly. If it is indeed a parasite causing the clouded eye, once placed in fresh water you can actually watch them burrow out of the eye. If it will eat, the tetra anti parasitic food wont hurt either. HTH