maybe it is a rare morph, because i don't know, but i thought muraena millaris where dark brown and had lots of yellow spots an i thought the common name was Golden Tail eel. maybe this is some type of bannana eel morph?
The banana eel is an uncommon amelanistic or xanthic morph of a much more drab-looking moray. The yellow color and small adult size (can be kept in a 40gal for life) make this a very sought after eel.