Red / Orange Crab

Uca sp.

Origin	Tropical intertidal mudflats and mangroves worldwide
Maximum Length	2 inches (including claw)
Minimum Tank Size	10 gallons with a land area (brackish paludarium)
Reef Compatibility	Not a reef animal — semi-terrestrial; see cautions

Behavior

The Red / Orange Crab is a fiddler crab, famous for the males’ single oversized, brightly colored claw that they wave to signal to rivals and females. They are lively, comical, and highly active during the day, constantly sifting substrate and interacting. Fiddler crabs are semi-terrestrial intertidal animals — in nature they live on mudflats and mangrove shores, burrowing in the sand and emerging to forage at low tide. They are best kept in a brackish paludarium setup rather than a fully submerged marine tank.

Diet & Feeding

Omnivore/detritivore. Sifts sand for algae, detritus, and organic matter. In captivity offer algae wafers, sinking pellets, dried seaweed, and occasional meaty bits. They filter mouthfuls of substrate for food, so a fine sand bed is important.

Cautions

IMPORTANT: Fiddler crabs are semi-terrestrial and need access to DRY LAND — they will drown or slowly decline if kept permanently underwater in a standard reef tank. Provide a brackish setup (a mix of fresh and marine salt, not full reef salinity) with a sloped sand bank or land area they can climb onto. They are escape artists — a secure lid is essential. Keep with peaceful tank mates only; males may spar over territory. Not suitable for a standard reef aquarium.