I've had one for a little over a year in our 55 gallon fish only tank. She (dark colored, not blue) was eating at the fish store, so my mom gave her a try and she's been eating silversides in our tank ever since. I would say this is 1 in 1000, so don't try it unless you want to go through lots of eels! The white ribbon eel mentioned earlier is a much better choice because of it's hardiness. I'll try to find a picture just for fun and post later.