Garden eel dying?

Hey all. I've had a garden eel in my tank for about months now and he
seemed to be doing fine. He would come out of the sand regularly and eat
brine shrimp ok. But now he's not looking so good. His entire body is out
of the sand and he is curled up in one corner right now. He has been moving
around aimlessly all day, I would almost say he went blind. His head is on
the sand upside down with the rest of his body. He moves if I touch him,
but then he just lays down in one place sideways or upside down. Anyone
have any advice? Everything else in the tank is doing just fine, including
an anemone and a hammer.