Fiddler Crab
Uca sp.

Care Level




Reef Compatible


Plant Safe


Max Size

Less than 2

Minimum Tank Size



brown, white



Water Conditions

74-84° F, KH 12-30, pH 8.0-8.2


General: The fiddler crab is often available in may pet stores, although those who purchase it need to understand it is a semi-aquatic crustacean that requires brackish water and sand to burrow in. A tank should be set up that is part water and part aragonite substrate, a small filter to ensure clean water, and structure such as driftwood and rocks.

Dimorphism: Males have a large claw, while females have two regular sized claws.

Fecundity: The fiddler will show breeding behavior in the tank, but very there have been very few documented cases of successful breeding. This is mainly because the fiddler crabs have a planktonic stage in the ocean before transitioning to adults, and the conditions for this stage are very hard to replicate outside of nature. When displaying mating behavior, the male will wave its large claw to attract females. In the wild they create burrows for spawning, and the female will hang onto the eggs until they hatch and begin their life cycle.

Water Chemistry: 74-84° F, KH 12-30, pH 8.0-8.2
Fiddler crabs like fairly warm, brackish water and a basic pH.

Aquarium Diet: Fiddler crabs will accept flake, algae wafers and frozen food such as brine shrimp and blood worms.

Compatibility: Fiddler crabs can successfully be kept with other fiddler crabs.

Fiddler Crab Photo Gallery

Fiddler Crab Videos

Author: Grant Stevens