Eels aren't like most fish in that they don't just eat and eat if you put food in front of them. My zebra eel would grab the shrimp I would put in the tank and pull away when he was done eating. Its typically good to feed it twice a week. With that size eel, it will probably end up becoming about 2 shrimp each feeding (depending on the size of the shrimp). The great thing about eels (especially zebra eels) is they are incredibly resilient and so easy to feed, because you just have to offer food infrequently, and if they eat it, cool...if they don't its not a big deal. Also, they can be prone to "hunger strikes". It's periods of time (sometimes up to 3 weeks) where they dont eat. Its nothing out of the ordinary, they just are able to do it and aren't constantly voracious or hungry.
