Our Privacy/Cookie Policy contains detailed information about the types of cookies & related technology on our site, and some ways to opt out. By using the site, you agree to the uses of cookies and other technology as outlined in our Policy, and to our Terms of Use.


Underwater Habitat for a Fiddler Crab

i Jeffrey Hamilton/Lifesize/Getty Images

Recognized by their one oversize claw, fiddler crabs are a small, active, easy-to-keep pet crab. Despite how you might find them in pet stores, fiddler crabs won’t be happy or healthy in a completely underwater home. Fiddlers need to be able to climb out of the water and get some fresh air.

About Fiddler Crabs

Fiddler crabs are a group of 90 species that hail from the brackish lagoons and swamps of Florida. Gold fiddler crabs are the most common species in pet stores. Fiddler crabs are only semi-aquatic, meaning they live both in water and on land. Males and females are easy to tell apart. Male fiddlers have one large claw and one small one; females have two small claws. Hardy and easy to care for, fiddler crabs can live up to three years and grow to 2 inches in length.

Tank Size

Because of their small size, fiddler crabs don’t demand a lot of real estate. A 10-gallon tank can easily house half a dozen crabs. If you plan to have several crabs, only keep one or two males with several females. Equip their tank with a secure lid, or your fiddlers may pull a Houdini.


Creating a fiddler home is akin to creating a tiny beach in a tank. Opt for live sand as a substrate. Along with having beneficial trace minerals, it helps maintain a pH level that is essential for your fiddler. One side of the tank should have at least 4 inches of sand, and the other side of the tank should have water lower than the level of the sand to create a miniature shoreline. Fiddlers need to be able to come out of the water to breathe air and dry out. You can decorate with rocks, sticks or plastic plants to give them a place to hide or climb. Be sure to leave an open area for your crab to burrow into the sand.


Fiddler crabs are native to the brackish waters in swamps and lagoons, so they will need some salt in their water. For each gallon of water in his tank, add 1 to 2 tablespoons of sea salt. Don’t use table salt for this; look for aquarium salt at the pet store. It isn’t essential, but a heater to keep the water in the tank in the 80s will be appreciated by your fiddler. Use an internal filter in your tank to keep the water clean.