How about an eel? But not just any eel, but a white ribbon eel, aka ghost eel. If you go for a ribbon eel just don't get the black or blue ones because they suck in aquariums. I can let you know where to get one if you're interested. Check out grimreefers.com in the "if only i had some jelly" thread in the eels section.
btw don't put jellies in there. You need a specialised circular tank called a kreisel to properly keep jellies. If you feellike it, you could do that too!
