Care Level: Easy
Live Plant Safe: With Caution
General Description: The Fiddler Crab is a unique, semi-aquatic creature that can make a fun addition into the right aquarium! There are over 100 speices of Fiddler crab in the genus Uca native to coastal regions. The ones often encountered in the aquarium trade come from Florida where they inhabit brackish marshes, lagoons and swamps. While these crabs are relatively hardy and unfussy, they do have some specific environmental requirements that need to be met. For starters, Fiddler crabs cannot live long term in a fully aquatic environment (see ‘Care Requirements’ below). The average Fiddler crab can live between two and three years, and reach an adult size of approximately 2″ across. Fiddler crabs are social and do best when kept in groups. Males can be distinguished from females by their single, larger claw. The waving of this claw is a way for Fiddler crabs to communicate with each other and make their presence known.
Diet Requirements: Fiddler crabs are naturally omnivorous scavengers. Offer a diet of high quality flake foods, pellet foods, frozen foods and sheet algae. Variety is the spice of life, even for these small invertebrates.
Care Requirements: An established minimum 10 gallon aquarium is ideal for small group of Fiddler crabs. Size up accordingly to accomodate a larger group. A secure lid is absolutely necessary to prevent these crabs from inadvertently escaping up cords or tubing out of the aquarium. Crabs are very intolerable of nitrite or ammonia spikes. Weekly or biweekly water changes are encouraged to keep water parameters up to standard (Nitrates < 20 ppm). Avoid the use of copper based medications as this will cause harm to, or even kill, your Fiddler crab. Given their environment specific requirements, Fiddler crabs tend to do best in a species only aquarium. Fiddler crabs are semi-aquatic, meaning they will require an area within the aquarium that is above the waterline. This can be constructed with aragonite substrate, which is preferred over just standard aquarium gravel, because this medium contains important calcium and trace minerals for the crabs to molt properly. The substrate should be deep enough to allow the crabs to burrow. The height of the water portion of the aquarium only needs to be a few inches deep to cover the majority of their body. The use of an internal filter will help keep the water clearer and from being stagnant. There are two ways to go about providing Fiddler crabs with their necessary salty environment. First, you can keep a true brackish aquarium with a salinity between 1.005 and 1.012. In order to achieve these, marine salt would be used rather than standard aquarium salt, and at a volume of 1/8 cup per one gallon of water. This route limits typical freshwater tank mate options, or live plants (with the exception of mangroves). If keeping a brackish aquarium is undesirable, then we suggest at least adding a standard tablespoon of aquarium salt per 5 gallons of water. Without salt at all, Fiddler crabs will have health issues that can lessen their lifespan. Tank mates such as livebearers (e.g., guppies, mollies, swordtails) can be adaptable to either a freshwater or brackish environment, making them a suitable match for a Fiddler crab aquarium. Keep in mind, however, that sometimes very small fish can be predated on by Fiddler crabs. Fiddler crabs are best kept as one male with several females. Recommended water conditions, 74-82° F, KH 12-25, pH 8.0-8.5.
Purchase Size: Medium: 1″ to 1-1/2″
Note: Your item may not look identical to the image provided due to variation within species. Purchase sizes are approximate.