Thanks for the article! I`ve read it with great interest as i have a zebrasoma that suffers from HLLE.
I bought the fish like that, the LFS told me its scars from a fight with another fish during transport and that they will heal "just fine"... Much later(a couple of months) I began to wonder why its wounds don't heal at all and I think I even observed the condition getting worse. :eek: I did read about HLLE but only saw an (very) old paper where the use of active carbon was "suspected" as well as an diet. Since I feed my fish frozen food twice every day and nothing else. I thought that it might be the non exiting variance in food and began to add vitamines, tried to offer fresh food as well and added garlic to the food. (soaking krill / mysis / artemia in it)
I watched the fish closely and thought at first that it got better, "maybe" the scars did heal a bit... but not that much.
Now... I do also use activated carbon since day 1 of my tank. I do wash it thoroughly before i use it and I only buy it from "high quality" brands like sangokai or nyos. However, as I just learned its probably a lot of it and its used in a high flow filter. (nyos torq) I use roughly 500g on a 350 liter system. Exchanging it maybe every 2 months or so.
I think the next step is to remove it entirely from my filtration and see if that helps.
EDIT: I believe I even read an article where it was stated that the only "proven" cause for HLLE is captivity.