The marbled crayfish or Marmorkrebs, is a parthenogenetic crayfish that was discovered in the pet trade in Germany in the 1990s.Marbled crayfish are closely related to the "slough crayfish", Procambarus fallax, which is widely distributed across Florida. No natural populations of marbled crayfish are known. Information provided by one of the original pet traders as to where the marbled crayfish originated was deemed "totally confusing and unreliable". The informal name Marmorkrebs is German for "marbled crayfish".
Marbled crayfish are the only known decapod crustaceans to reproduce only by parthenogenesis. All individuals are female, and the offspring are genetically identical to the parent. Marbled crayfish are triploid animals, which may be the main reason for their parthenogenetic reproduction. Marbled crayfish are thus a model for the rapid generation of species.
Because marbled crayfish are genetically identical, easy to care for, and reproduce at high rates, they are a potential model organism, particularly for studying development. A major drawback, however, is the long generation time (several months) compared to other research organisms.