Procambarus alleni

The Everglades crayfish, sometimes called the Florida crayfish, the blue crayfish, the electric blue crayfish, or the sapphire crayfish, is a species of freshwater crayfish endemic to Florida in the United States. Its natural range is the area east of St. [Johns River] and all of Florida from Levy County and Marion County southwards, as well as on some of the Florida Keys. It is included on the IUCN [Red List] as a species of Least Concern. The blue crayfish is frequently kept in a freshwater aquaria. In the wild, this species varies from brown-tan to blue, but an aquarium strain has been selectively bred to achieve a brilliant cobalt blue color.
It should not be confused with the burrowing Cambarus monongalensis, also known as the blue crayfish, but native to Pennsylvania, Virginia and West Virginia.