If it's the biggest your tank is gonna be then don't. It's like putting a tang in a small tank for it to "grow out." It never will because it will get stunted if it lives that long and doesn't get ich from stress.
It's a matter of principle in this situation, I would never recommend any eel for any tank under 125G. I'm with Flake on this one, she doesn't have that much rep from being witty (even though she is
). It's from her experience and knowledge in the hobby.
And most eels I've seen do swim quite a bit, added the mess they create and poor sight meaning knocking things over would be unimaginable and would need daily PWCs to keep water standards at an "okay" level.
eels are more of an experienced aquarists animal and should be treated as such.