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Fiddler Crab – Complete Care Guide

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fiddler crab male

Fiddler Crabs are some of the more common crab species kept in captivity. The males have an incredibly large claw that they use for calling out to females and also for sparring. The female does not have a claw this large but instead has two really small ones. Under the proper conditions, the Fiddler Crab is a pretty hardy invertebrate.

This beautiful invertebrate will grow to be roughly 2 inches in length when it is full size. This crab and many others are interesting to watch when they are searching for food in their habitat. The Fiddler Crab is not too picky when looking for a meal but we will go over that more later in this article.

Aquarium Requirements

Keeping Fiddler Crabs alive and thriving is not incredibly hard. They do not get incredibly large but enjoy living in groups. They should not be kept in anything smaller than a 10-gallon aquarium and it is not recommended to keep more than one male in an enclosure due to the high possibility of aggression between males. In the wild, they spend most of their time in inter-tidal flats or lagoons. Because of this, it is important to provide a land area for the crab because they are not fully aquatic crustaceans.

Mimicking an ocean beach habitat is ideal for this crab. It normally lives in brackish water so providing a little bit of marine salt in its enclosure is ideal. Use a refractometer, like this one from Amazon to check the salinity levels in the water. To maximize the health of your crabs keep a filter, pump, or something similar to move the water around. Also, using aragonite sand to help keep increased pH levels is recommended. The crab will also use this substrate as a calcium supplement!

The Fiddler Crab requires the following water parameters:

  • Water Temperatures 74­­°-84° degrees Fahrenheit
  • KH between 12 and 30
  • pH: 8.0 & 8.2
  • Salinity levels between 1.005 and 1.012 sg.

The enclosure should also be full of rocks and other decor to provide places for this crab to climb and hide. Be sure to leave enough space to allow your Fiddler Crab to burrow. Crabs are notorious escape artists so a tight-fit lid is a must-have. The sealed aquarium will also help to keep humidity levels higher.

Food & Diet

Fiddler Crabs are omnivores and are not picky eaters. They will happily eat algae that grow in the aquarium’s waters but will also eat pellets, flakes, bloodworms, and small shrimp! It is important to provide them with a well-rounded diet. I feed mine all sorts of food. I will treat them to small pieces of carrots, apples, lettuce, pellet food, and flake food.

Tank Mates

Finding tank mates for Fiddler Crabs is hard because they enjoy being in brackish water and the design of the enclosure does not usually provide enough water for fish. If your setup has enough water, fish such as platys, mollies, swordtails, and guppies are good choices. They enjoy living in brackish water, unlike many other species. Be mindful that Fiddler Crabs will occasionally try to take a snag at the fish so the fish may become lunch for the crab. Nerite snails should be a fine addition to a brackish water enclosure as well.

Other than that, as stated above, unless the enclosure is incredibly large only one male should be kept with an assortment of females. The males have a higher chance of fighting and possibly injuring/killing each other while sparring for females.


Breeding Fidler Crabs is incredibly difficult. They require a deep sand bed so the female can burrow into it. Once mated, the female will stay in the burrow for roughly two weeks with her batch of eggs. Once that is completed she will expel the eggs into the water but it can only be successful if the water is marine water. This will require a higher salinity level. If this is possible the baby crabs need to be fed rotifers and live baby brine shrimp until they are large enough to eat different types of food. I have had a female successfully hold eggs, but nothing ever comes of it because I cannot replicate the requirements needed to get them to hatch.

Final Notes

Fiddler Crabs are an interesting and unique animal that can be kept at home, provided the enclosure is right for them They have beautiful colorations and a very cool shape to them. They’re fairly active and a joy to observe. Unfortunately, they require a very niche habitat that is not suitable for many other animals but if you can provide the correct setup for them, they will be wonderful pets. If you love crabs, but Fiddler Crabs are not for you, check out 9 Unique Terrestrial, Semi-Terrestrial, Brackish & Freshwater Crabs to learn about other types of crabs available!

Featured image by Wilfredor on wikiMedia

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