hey, i have had a 7" tire track eel for about 3 weeks. he is in a 55 gallon with a small oscar and a pleco. i have not seen him eat, let alone stick more than his head out of the tank. i have talked to my local fish store and they say he is probably eating at night but im not sure if the pleco is getting all the food first. any recomendations for foods? is this normal behavior?