We had gotten the male first, then the female. Here is a shot of them together, the first day we brought the female home. They seemed to like eachother instantly. She immediately began to burrow, using her big back flippers like shovels. They were sitting in this ten gallon tank while we prepared their new home.

The female is a bit larger than the male. In this picture, she's on top. Notice she has much more contrast in her skin tones. Her back looked like it had dirt on it when we got her. She's even got more of a girl's face, I think. On occasion, when she's darker, we sometimes have to look at them both to distinguish who is who, but its usually easy enough to tell on first glance.