I have 3/1 of them since two weeks. The female is half the length and and a quarter of the weight of the males. You can see here in the background in the third picture.
So far they are quite peaceful and very courious. And they love currents. When they are not digging they sit together on a rock in the current and wait for food.
In the wild they eat Aufwuchs from the rocks and small insects. They can swallow pretty big foods comparad to their body size.