The Caspian Mud Shrimp can live in salt or freshwater and grow up to 8mm long. It is thought that its introduction to Great Britain occurred from the release of ballast water from trading ships. Their rapid growth rate and high fecundity (ability to reproduce quickly) have made them successful invaders. They affect habitats by changing the physical structure of riverbeds and inhibiting certain species. They have been spotted mainly in the lower part of the River Thame catchment, near the Thames.