Pithos Crabs or Pithos Mirabilis make a great addition to any CUC (Clean Up Crew). Reef safe, but some say they pick at corals, possible this is due to decay or failing coral. They are and excellent choice as they will eat algae, filamentous such as GHA (Green Hair Algae) and bubble as well as scavenging for left over food and other waste. While similar to Emerald and Ruby Mithrax Carbs, they tend to be more active and slightly larger.