they'll probably be alright together but what id be worried about is that you have a garden eel in a tank. they get several feet long and like to bury their bodies vertically in the sand so they can just pop in and out of their burrow for safety, if they have to adapt to a shallow sand bed they tend to burrow sideways and half the time parts of their body stick out. they wont be able to just pop in and out and more than likely that will stress them out more than they need to be. also they like to feed on small particles floating by. you might be able to get it to eat frozen but either way its not very well suited to aquarium life unless you can provide it with a huge setup with 4-6 feet of sand bed.
sorry, im not trying to be negative. just trying to give you the facts. i used to want one for my tank so i did a bunch of research and everything i could find said that its not suited for small aquarium life.