The ich is probably brought out from the into of the new fish to the tank. The HLLE could of come from the previous owner / store from not feeding him correctly.
I order a purple tang from PETCO online and he came with HLLE. He to was eating fine when intro duce to the tank. Two days later he got ich and so did a few other fish. (NO I did not QT him, that was dumb on me, different topic).
After a week or two, more I would say 2, the HLLE cleared up. Now, if you look close at the Purple Tang, you will see scaring from the HLLE, but like I said it cleared up from a better diet and different food options. I also used Omega flakes with garlic to boost his immune system.
That was 8 months ago and he is doing great!!!