MicroCcrabs, Limnopilos naiyanetri are often called spider crabs. These crabs come from a river in Thailand and live their whole life underwater. They are small crabs and only get a 1/2" inch in size, and are quite peaceful. Many people keep them with shrimp without incident. We feed them tropical fish food alond with a variety of frozen foods. They are really interesting inhabitants in your tank that are truly fun to watch.