Mural Goby Behaviour?

[stang1]

We brought a pair of Gobies a few weeks ago believing them to be Chalk Gobies. After spending a bit of time on google, it seems that they are Mural Gobies.
They generally stay together and are really peaceful fish. Earlier, my partner noticed them swimming around each other in a circle and when he looked later one of them had disappeared into a burrow. After a while, it darted out and looked as though it had burrowed right into the sand. It has now disappeared again and the other one appears to be waiting around for it. We've never noticed this behaviour before and were wondering if anyone could shed any light on this behaviour?
Many thanks,
Angie

 

[n3ont3tra]

I'm not sure what 'mural' means... But my pinkbar goby dug a small burrow and pokes his head out. And he gets food that drifts by. I hope this helps.

 

[littleme1969]

Mating bahaviour maybe