The main problem is that they can keep the sand clean of everything, including pods. If you have no ambitions for mandarin dragonettes or scooters, you're fine...uh,---well, one other detail: they can shift your rockwork if you have anything precarious. I made my own tank ready for them by putting down eggcrate under the sand and rock, but I love mandarins, so there we are: no diamonds. My yellow watchman does a moderate amount of sand-sifting, but he's far from efficient. Some others have named the court jester goby as a sandsifter, but since he's only about an inch or two long, he's not every effective. Diamond gobies, on the other hand, are major redecorators. Nothing escapes them.
