I had a pair at one time. They got along fine for a bit they would always be side by side sifting away. They would makes homes around the tank under the rocks and shared them. There must have been a fight one day because they started keeping to separate ends of the tank and keeping their own little holes. Not sure what went wrong.
As far as the rock work goes. They liked to dig under everything to build their dens. I never had any problems with them moving the rock work. I put my rocks in then sand so that may have helped
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