Head & Lateral Line Erosion "HLLE": Symptoms - HLLE literally looks as though the skin is rotting or peeling off the fish. Affected areas usually include the face and lateral line, and may be white in color. Treatment options - This is more of a condition than an actual disease. Since no one can agree on the exact cause, all you can do is address all of the following theories regarding HLLE: 1) Stray voltage - Use a titanium ground probe & test your tank for stray voltage. 2) Running carbon - Don’t use it, or use only premium grade carbon. 3) Nutritional/vitamin deficiency - Feed high quality nutritional foods. Some have had success reversing the effects of HLLE by soaking food in “fish vitamins” and also feeding nori. 4) Copper exposure - Sometimes fish treated with copper (especially tangs) will develop HLLE. It usually "heals" post treatment, but food soaking a vitamin supplement is a good idea to help expedite this.