This big guy was a hitchhiker!! That's the big leather behind him,I'm not even sure when he first appeared in the tank! BUT as you can see he is fat and sassy! For a critter without a brain they sure can move when it's feeding time!! lol
You might want to wait a bit longer before you add one though.. most are sand sifters and need a mature tank to do well even if they are fed.
Good luck!