I have a pair, my female is larger and fatter. Getting the pair was just luck though, I paid $30 each for them when they where 12" long. You don't see them for sale very often. These two where the first I saw in a long time and I haven't seen anymore since I bought these two(about 2 years).
They are pretty fun to keep. They don't touch the fish they are kept with, which range from 1" to 3" in size. They are both in a 55gal and can burrow completely under the substrate if they feel threatened. They can also move well out of water, my glass tops are heavily taped down to keep them in the tank.