i just put a couple pieces of rock in the fuge just for the critters to hideit really doent do much.the rock in your DT does the most.to me the rock in the fuge collects to much deitrus and can be more dentramental.plus you dont want much of a clean up crew in the fuge because they can ruin your pod collection.i would say keep it to a minimal .maybe just a few pieces of rubble