Atlantic Marsh Fiddler Crab

Geographical Origin and Habitat: Eastern coast of North America, common from Massachusetts to Florida. Inhabits intertidal mud flats and salt marshes.

Taxonomy: Member of the family Ocypodidae, genus Uca (often classified as Minuca). Features extreme sexual dimorphism.

Social Behavior: Semi-terrestrial. Digs deep burrows in wet mud or sand, spending much of its time on land interacting and waving.

Coloration and Sexual Dimorphism: Carapace is dark, brown or muddy green. In males, the single giant signaling claw is yellowish-white or cream.

Tank Setup: Requires a paludarium setup (land and water). Essential to provide a dry land area of moist sand for burrowing behaviors.

Diet and Feeding: Detritivore. Filters sand/mud for organic particles. Accepts crushed spirulina wafers, sinking herbivore pellets, and frozen foods.

Water Quality: Brackish water with salinity SG 1.005-1.015. Highly adaptable, preferring temperatures between 15 and 25 °C.

Compatibility and Tankmates: Peaceful. Unsuitable for deep aquariums. Best kept in small harems consisting of one male and multiple females.

Aquarium Breeding: Females carry egg masses under their tail, releasing planktonic larvae into saltwater during high tides. Spawning in tanks is rare.

Risks and Diseases: Drowning risk if kept in a water-only setup without land access. Excellent climbers; a tightly sealed lid is mandatory.