I use sand for mine. Usually I will let the cubes soak in a little cup of water, then put it in, thats if he wont go after it. Try Beefheat. That always works good for me. Or you can go to wal mart and get those tiny salad shrimp, Mine love those. And I would def get him more stuff to hide in in that tank like plants and maybe a peice of driftwood that he could go under