Mine isn't overly shy and yes when hungry they will take the odd snap at a passing fish, they can do fin damage. As they get bigger they get bolder.. I had mine in with some juvenile fish (not small juvies) and watching the tyre eel predate was amazing, he actually had ambush tactics :lol: He worked in a slow motion till he was close enough and then snap!
Mine prefers mysis shrimp, blood worms, earth worms, tubifex, he won't touch any form of flake or granule based foods.