Firstly, did you treat your fish properly in a QT tank? Or if you have no inverts/live rock, did you treat the main tank? Also, what method did you use for getting rid of the ich? Chemicals out there, won't kill the ich parasite and its life cycle, it will only remove it from your fish, for a set amount of time. The ich parasite will STILL be present in the water column. Therefore, once the fish is rid of the ich parasite, by chemicals, it will acquire the parasite all over again because it has not fully been exterminated, and remains in the water column. The only things that i know of that successfuly kill the parasite, is Hypo treatment, and Copper medicines.. But Copper kills inverts, and turns live rock brown, which is why it's best to use Copper in a seperate tank.
Anyways, did you have the light off, and then when you went to feed him, you turned the light back on? After observing the color fade, does he ever go back to his normal color, and then back to the faded color? A lot of times, fish when they are sleeping, or just chilling out in the dark, their colors will fade. But then, after spending time in the light, they will regain their colors. This phenomina has scared many aquarists, thinking their fish are dying or have obtained some sort of disease. When in reality, it was just the normal behavior of the fish.
What are you feeding the eel as well?
Also, can you list your water parameters here? So we can at least rule out that something isn't going on in your tank. Nitrites, Nitrates, Ammonia, pH, the works.
