I have a 6g with a pistol shrimp in it and some live rock this shrimp digs all over the place I wanted to know if I add a pistol shrimp to my main tank will they dig so much a to cause my live rock a tumble over it seems they dig out all the sand from under the rock, also will the pistol shrimp attack and eat pepermint shrimp in the tank or are they reef safe and just spend all day making holes.....:birthday: