Fiddler Crabs

Fiddler Crabs are an interesting and unique species of crab that can make great family pets. They are small, usually no more than two inches in size, and come in a variety of colors and patterns. Fiddler Crabs are native to the coastal regions of the Atlantic Ocean, but they can also be found in other parts of the world.

Fiddler Crabs are social creatures and do best when kept in groups of two or more. This means that if you’re looking for a pet crab, you’ll need to purchase at least two.

Fiddler Crabs are small crustaceans found on both sides of the Atlantic as well as in parts of the Pacific ocean. In the wild they’re typically found in saltwater marshes or sandy or muddy beaches. While they’re found in some aquariums, because they need brackish water to survive, it limits people’s interest in them. 

They’re very hardy and can survive in a wide variety of conditions. They are omnivorous, meaning that they eat both plants and meat.

Fiddler Crabs make great aquatic pets for anyone interested in keeping sea creatures. They are relatively easy to care for, requiring minimal maintenance. They are also very inquisitive, and will always want to find out what’s going on around them. They are territorial, and will defend parts of an aquarium that they consider theirs. 

Fiddler Crabs make great pets for anyone interested in keeping a collection of unusual aquatic life. They are also a lot of fun to watch, and are entertaining to look at while they scavenge for food. They are also very entertaining for children, and will happily entertain them while parents are busy doing something else. The biggest downside to owning a Fiddler Crab is that they don’t live very long. Most die within 3 years. 

Fiddler Crabs require special care and attention. They need access to both land and water, so you’ll need to provide them with a tank that has both a dry and wet area. You’ll also need to provide them with plenty of food, such as small pieces of fish or shrimp, and make sure their water is kept clean.

They’re relatively easy to care for, but they do require some special attention. They’re not the best choice for first time pet owners , as they require more care than some other types of crabs. However, if you’re willing to put in the time and effort, Fiddler Crabs can make great family pets.

Overall, Fiddler Crabs are a great pet for those who are willing to put in the time and effort to care for them properly. They may not be the best choice for first time pet owners, but if you’re looking for an interesting and unique pet that will bring lots of joy to your home, Fiddler Crabs are definitely worth considering.

Fiddler Crabs Information

  • Average Length: up to 3 inches
  • Colors: Brown or Orange
  • Attention Needs: Low
  • Tolerance to Heat and Cold: No
  • Good Pet: Yes!
  • Good with Other Crabs: No
  • Good with Other fish species: No
  • Good for Less Experienced Pet Owners: Yes
  • Health Concerns: Shell Diseases and Appendage Loss.
  • Average Life Span: up to 3 years in captivity

Fiddler Crabs live in the Eastern Pacific, Indo-Pacific and on both the sides of the Atlantic. They are typically found in coastal areas that have brackish water like salt marshes, sandy beaches and mangroves.

Physical Appearance of Fiddler Crabs

Fiddler Crabs are made up of about 100 species of closely related crabs all grouped under genus Uca. They can have a variety of colors and patterns, but most Fiddler Crabs will be brown or orange.

A distinct feature about Fiddler Crabs is that they have a large claw. Their large claw looks similar to a fiddle (violin) and that’s how they get their name, ‘Fiddler Crabs’. They use their large claw to defend themselves, communicate with other crabs or court females. Male Fiddler Crabs have one large claw (often called major claw) and one small claw. Females don’t have a large claw, they have two small claws. For some varieties of Fiddler Crabs the larger claw is bigger than their entire body.

They are small crabs that only get up to 3 inches long, with males growing larger than females.

These crabs have both lungs and gills and can breathe in water and on land.

They have two eyes sticking out from their head, a pair of antennae and a rostrum (extension of their carapace) on the front of their body. Their antennae help them scan their environment.

Temperament of Fiddler Crabs

Fiddler Crabs are generally non-aggressive but sometimes male Fiddler Crabs get aggressive. The males will fight over territory or for a female in their tank. If you see them fighting, move the aggressive male Fiddler Crab to another tank, or the other end of your tank if another is not available.

They shouldn’t be handled because it can stress them. They are usually non aggressive but if threatened, they can hurt people with their claws. They will often wave their claws to communicate.

Best Habitat for Fiddler Crabs

Fiddler Crabs are semi-terrestrial crabs. They can live both on land and submerged under water. Setting up their tank needs a little more effort than what it takes for aquatic crabs. Their tank needs to have a dry area to let them come out of water. If they don’t have access to dry land, their lifespan will be greatly reduced.

All crabs are good climbers and the top of their tank should be tightly secured. The best option is to use a mesh top because it keeps the tank secured and ventilated.

Their tank should be kept in a warm area away from direct sunlight.

Tank size

A 10-gallon fish tank will be large enough to hold 2 to 4 Fiddler Crabs. For every additional Fiddler Crab, you’ll want to add 5 gallons to the size of your tank.


Their water temperature should be kept between 75°F to 86°F.

Water Hardness and PH

The water pH should be between 8 to 8.3. The water hardness should be between 15 and 30 dKH


They don’t have specific lighting needs.

Tank Substrates

The substrate should be arranged to create a slope for dry land inside their tank. Sand is the recommended substrate because it will let Fiddler Crabs burrow and filter for food. To set up their tank place a layer of soft, sandy substrate on the bottom of the tank. Arrange the sand in a way so that the sand slopes upwards to one end of the tank. By piling up sand on one side your Fiddler Crabs will be able to come out of water when they want.

Don’t use gravel because it is hard and your crabs won’t be able to burrow. Gravel can hurt your crabs.


Fiddler Crabs don’t do well with living plants because will damage them. Small artificial plants can look nice without worrying about damage.

Rocks and driftwood can be used to create hiding spots and give them space to climb.

Tank conditions

Some owners think Fiddler Crabs need freshwater but they need brackish water. Brackish water has a slightly higher salinity than freshwater but less than saltwater. Creating brackish water can be a little challenging for new fish tank owners.

To increase the salinity of water, first set up the tank like any freshwater tank. Then add aquarium salt to the water. The instructions to add aquarium salt should be mentioned on the product you use. Use a hydrometer to check the specific gravity of water.

The specific gravity (salinity) of your tank water should be between 1.01 to 1.08. Specific gravity is a term used to measure the salinity level of water.

Tank Maintenance

Adding a filter is optional but recommended to keep the tank clean. Don’t use a hang-on-back filter. Your Fiddler Crabs may try to climb it and escape.

A 20% water change should be done every other week to make sure the water has low levels of ammonia and stays clean. Regular water changes will keep the toxic compounds from building up in your tank.

Best Tank Mates for Fiddler Crabs

Fiddler Crabs live in groups and at least a pair should be kept together. They don’t do well alone because they get lonely. More than a pair are great but then a they’ll need a larger tank to make sure there is enough space for all of them.

The down side is that these crabs have limited options for tank mates. One reason for fewer tank mates is Fiddler Crabs need brackish water that most freshwater fish can’t handle. Larger fish cannot be kept with them because they will attack or eat them.

If you want to create a community fish tank, consider:

  • Mollies
  • Guppies
  • Bumblebee Gobies
  • Swordtails

Any fish you add to their tank will need more water than your Fiddler Crab needs. The tank size and setup should be adjusted accordingly.

Health Issues

Fiddler Crabs are hardy and usually don’t get ill. Common health issues that they can have are Shell Diseases and Appendage Loss.

Shell Disease

Shell disease is an infectious and contagious condition that can be caused by a variety of different stressors, including poor water conditions, low dissolved oxygen levels, and inadequate nutrition. It occurs when opportunistic bacterial or fungal pathogens take advantage of weakened immunity in the fish and begin to invade their shells and scales. The lesions created by the infection can be visible to the naked eye, as white or yellowish patches, or they may be hidden beneath the surface. Left untreated, shell disease can be fatal to fish. It’s fatal because it prevents them from being able to breathe or digest food.

Appendage Loss

Appendage Loss is a serious condition that can lead to the loss of fins, tail, or other appendages. This condition can be caused by a variety of factors including infections, parasites, and bad water chemistry. It’s important to identify the symptom and diagnose the cause in order to effectively treat this condition before it leads to more serious issues.

By taking the time to inspect your fish regularly and create a healthy environment for them, you can help keep your fish healthy.

Feeding Fiddler Crabs

Fiddler Crabs are scavengers and use their claws to filter debris from the substrate and find food. They will eat anything that is nutritious like algae and fungus.

Females have an easier time filtering food because of their smaller claws. The large claw makes it difficult for males to filter food.

They can be fed commercial crab food like shrimp pellets and frozen plankton. Vegetables like zucchini, lettuce are also good for them.

Fiddler Crabs should be given calcium supplements because calcium helps with hardening their new exoskeleton that grows after molting. Adding a few egg shells to the water can be a good source of calcium for your Crabs.

They should be fed once a day.

Reduce the amount you feed them if the ammonia levels increase in your tank.

Related Questions:

Can Fiddler Crabs Breed in Captivity?

They might try to mate in captivity but they won’t be successful giving birth to offspring. The male will often signal and court a female with their claws. If the pair mates the female will soon start carrying eggs but the conditions the larvae need are not available in captivity.

The Fiddler Crab’s larvae are planktonic, meaning they float on the ocean’s water column for a few weeks. After floating on the water column for a few weeks the larvae head back to the shore. In captivity this is not possible.

What Happens if They Lose Their Large Claw?

If a male Fiddler Crab loses the large claw, the other smaller claw grows to become the new large claw. Then usually the new claw that grows becomes the smaller claw.

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Maryna is an animal expert that has had dozens of animals in her life over the years. She has never found an animal that she didn't love immediately. It seems like every year she finds kittens that have been abandoned by their mom and she nurses them to health and finds homes for them. She contributes her vast knowledge about animals and family pets to our website and we're forever grateful to have her working with us. She's also an amazing graphics designer and has designed all of the social media images that we use across all platforms.