i'm assuming you mean a predator tank right? I had a snow flake eel in my predator tank, it was cool, and it was pretty small, It didnt grow very fast and was a good eater. I fed him silver sides.
tesseleta is to big for a 90, but I can say that a garden eel stays very small but you must have a deep sand bend and they are not the easiest to keep, also a zebra might do well since it is very passive and it will not eat any fish.
Yes, a green wolf eel will eat anything he can get in his mouth. Mine does anyway. But he is a very cool eel. (actually a fish I think) Thats why I still have him instead of going with smaller fish, like my wife wants to do. But she loves ole nessy too.
Go with a zebra, they are not supposed to bother your fish at all. They will eat shrimp and crabs though. The green wolf eels is acutally a dottyback and it will harrase and eat your fish.