Seriously though--you cannot --- an eel by external characteristics. Eels also undergo --- changes from male to female as they age (or so many of the moray websites say...)
Put a beer by one side of the tank and a smirnoff or some other cheer beer on the opposite... See which side the eel swims to.
I have tried this many times. They dont move to either one. They stay in the same spot. what is wrong???:help: