Rhithropanopeus harrisii (common names include the Zuiderzee crab, dwarf crab, estuarine mud crab, Harris mud crab, and white-tipped mud crab), is a small omnivorous crab native to Atlantic coasts of the Americas, from New Brunswick to Veracruz. R. harrisii is usually found in brackish water, but can also be found in freshwater. It likes to live on stones and in oyster beds. The crab can reach a maximum size of 20 millimetres (0.8 in). It has an olive-green-brownish color, sometimes with dark spots on its carapace.