Digging? I have a solo Tomato that fans the sand out of a particular place in the tank, is this what you are talking about? I don't know the purpose of the behavior. I think he might be testing me to find out if my LR is really on the bottom glass(j/k) Might be realted to territory? I have a coral beauty in the tank with him, but they get along great. Would also like to know the meaning of this behavior.