Zac, read some on eels, I had suggested that you try places like marinedepotlive.com amd liveaquaria.com for your preliminary research. There are too many eels out there to just generalize, but if you want a generalization, then YES, eels eat fish.
Success in this hobby requires that you learn to do your own reading, and not just on message boards. Read books, articles and then come here to ask for clarification or questions that your reading doesnt answer. It isnt that I do not want to help you, but I see a tendency that you do not even begin to look for your own answers and you need to learn to do so.