my snowflake would never eat a fish i didn't give him personally.
He was the nicest fish i have ever had. He slept with my porcupine puffer, and protected my small blue damsel from my lion. That lion wanted to eat him soooo bad.. haha...
it all depends on the eel. I have heard stories that they can be realy mean. But i fed mine big shrimp and live crabs, so i think he liked the crabs more the fish (they do eat crabs in the wild)