Hi all, I have a 13.5 gallon nano tank that has 2 clownfish, 1 emerald crab, and misc. corals in it. I am looking for 1 more fish that I can add to help stir up the sand. I have tried snails and red and blue legged crabs but for the life of me I cannot seem to keep them alive. It seems I fall into a cycle, get cleanup crew, gets rid of algae on sandbed, they die, algae returns some and repeat again.