So, we got this fish a couple months ago. In the tank was a Cichlid Stone and it was in there all the time. So, I got a Cichlid Stone too.
It took about 2 weeks before it would go into the stone at our house. Then it became its domain and it was boss of that stone. No one else came near that stone.
Then we decided to put a shell in the tank for the calvus. Guess who is now boss of the shell. There is hardly room for it in there... but that is the new spot. King of the shell.