Fying sand

[scarecrow]

My damsel has been spinning his tail in the corner of tank causing sand to go flying and he has made a deep section in the sand what is this ?

 

[mr. limpid]

He is creating a nest. Do you have just one or two of them? My clowns do that to, I added larger size gavel in that area so they can't kick it out as easy. They still manage to get some out but not all.

 

[scarecrow]

I have 3 damsels and two clowns but it is just the 1 damsel