I agree with NOOT. Mastecebeliid eels are very interesting fish, and the larger one's I've had (armatus included) will eat almost any living thing that comes within reach when hungry. They're fun to watch, too. Deceptively quick when pursuing prey. Most can be hand fed once they're used to you and their surroundings. They are (however) great escape artists like most "eels", so care should be taken with openings in the tank. I personally use hand-cut pieces of styrofoam to block the holes in the top of my acrylic tank where my heater and filter tubes go.
On a side note, I just bought a small (7.5") specimen at my local Petco that was being sold as a tire track eel (for 12.99 no less), but looks a little more like a juvenile dayi to me.
Sorry for the long post, but the spiny eels are a particular favorite of mine.