I'm not sure if it's sick, because I do not think that is a tyre track eel...
I'm not sure what it is, possibly a young American eel?
Either way, it should not be in a 10g tank, as it'll rapidly outgrow that and if it is sick, the stress of being in too small a tank won't be helping it.
I'm assuming it came from a pet store that didn't tell you (if they thought it was a TT) that it'd grow to over 3 feet long, and need a minimum 130g tank?
An American eel is no better, hey get equally as big (male/female depending).
How long have you had it? Sick or not, you may wish to return it, although personally I'd try getting it healthy first.
Since we don't know what the issue is, for now I'd say 30% daily water change to keep the water pristine and see if any symptoms develop/go away.