Possible Causes
There are many "theories" as to why this disease occurs, but there seems to be no single definitive answer that can be pinpointed or solely connected to it. Many of the contributing theories include stray voltage in the aquarium, poor water quality and environmental conditions, high nitrate levels, lack of vitamins and poor nutrition, stress, parasitic infestation (a protozoan, Octomita necatrix), using carbon, and that some fish may just be genetically pre-disposed to this disease condition, such as Tangs & Surgeonfishes (refer to sixth discussion down).
Treatment
Most of the above possible causes can be easily addressed. Stray voltage induces stress, so adding a grounding probe to the aquarium is a wise thing to do in any case. For poor water quality and environmental issues, follow good regular aquarium maintenance routines. Reduce and eliminate any other stress inducing factors, correctly diagnosis for parasites and always feed fishes foods that any particular species require in their diets.
Using over the counter medications do not seem to do much in treating this disease. However, those that contain antibiotics can help to treat for secondary infections. From all the research we have done, no matter what the actual "cause" may be, it appears that improving water quality and providing supplemental vitamins and adequate nutrition are key elements in "treating" HLLE. Many aquarists have had great success in reversing the effects of this disease by providing the fish with supplemental vitamins, such as A, D, E or B's, as well as iodine. This can be accomplished by feeding them foods soaked in Selcon, Zoe or other liquid vitamins, providing algae eating species with vitamin-rich live plant sources, such as macroalgae, i.e. Caulerpa (refer to the third discussion down) and adequate live rock growth, and even by feeding a diet of broccoli supplemented with peas and other prepared foods.
P.S.. i have also been told that activated carbon is a suspect and therefore you should only use it for a few days in any given month then remove it.2 of my fish had it at one point so i added a ground probe and removed my carbon after about a month one fish was healed,the other fish recovered and is quite happy these days but he has a permenant battle scar on him,he is my favorite fish simple because he has survived ick as well as lateral line,Hes a true soldier.
[ May 08, 2002: Message edited by: smokie ]</p>