Octagonal 33 with a full glass top? That isn't one of those coffee table tanks, is it? If it is, Elephant Noses are entirely unsuited to it. They need quiet and dim lighting.
Frankly, elephant noses are unsuited to any but the most experienced of aquarists. If you are in that group, my apologies, but my gut tells me otherwise. They are finicky about food, substrate, lighting, water quality, medications, and tankmates, and can be territorial with each other. As Julie mentioned, they get up to 8 to 12" long, so you don't really have room.
Now, You may have room for a single ropefish. Won't be the happiest critter in the world, since a) it'll be a little cramped, and b) ropefish prefer to be in groups, but it can be done.
The only green eels I know of are morays, american and european fresh water eels, and congers. Morays and congers are saltwater. Freshwater eels can get up to 2 feet long (or at least that's the biggest I have ever caught) and are pretty savage predators. Are the snouts pointy, bottle shaped, or bullet shaped? Is the body more or less cylindrical, or is it flattened? If it's a spiny eel, then maybe, just maybe, depending on the species you might have room. I suspect it will spend all of it's time dug in to the substrate, but there is room for it.
You have room for maybe 2 African Butterfly Fish
. Give them at least 2" of airspace so that they're not constantly bumping the cover. Grow some vals or onion plant up so that the leaves trail over the water surface and give them some cover.