If possible, choose a tank location that consistently stays between 68 and 78 °F (20 and 26 °C). Make sure the location is not exposed to direct sunlight, though, as it is harmful to crabs. [2] X Research source These tank estimates are the same whether you plan to keep fiddler crabs (which are saltwater crabs) or land crabs (which are freshwater crabs). Halloween land crabs, rainbow land crabs, and fiddler crabs are the most common pet crab varieties.
Aquarium sand is screened, cleaned, and sanitized in ways that other types of sand may not be.
In other words, if you’re looking at the tank from the side, the left (or right) one-third should have 2 in (5. 1 cm) of sand in it, the right (or left) one-third should be filled with 5 in (13 cm) of sand, and the center one-third should slope between these sand heights.
Stir in more marine salt to raise the salinity, or add more water to reduce the salinity. You may need more or less water than this, depending on the size of the tank. Add the marine salt at the same ratio: 1 gram (0. 035 oz) per 1. 5 liters or 0. 5 tsp per 1 gallon. Don’t use tap water without dechlorinating it first. Fiddler crabs are sometimes advertised as freshwater crabs by pet retailers, but they live much longer in brackish (low salt level) water.
The amount of water you’ll need depends on the size of the tank. A good starting estimate is 2 US gal (7. 6 L).
A sandy shoreline is the natural habitat for fiddler crabs and land crabs. They should have access to both shallow water and sand that they can dig into.
Using an aeration pump requires you to change the tank water more frequently, but, if you do so, the crabs will be just as healthy and happy as if you use an aquarium filter. Aquarium filters and aeration pumps are available at pet supply retailers. Follow the specific setup instructions for your chosen model.
Fiddler crabs require a temperature range of 75–86 °F (24–30 °C)[9] X Research source Halloween and rainbow land crabs require a temperature range of 68–77 °F (20–25 °C)[10] X Research source
Frozen shrimp and plankton from the pet supply store. [11] X Research source Dry or fresh seaweed. Lettuce, zucchini, apples, and potatoes. Raw fish. [12] X Research source Hermit crab food pellets. Fish food flakes. Dry dog or cat food.
During times when there are no molted exoskeletons in the tank, add some cuttlefish bones, which are available at pet supply stores.
Crabs don’t need hiding spaces, since they dig into the sand to conceal themselves. They also don’t need specific toys to occupy them. Just try different items and see which seem to appeal to the crabs.
Add a bit more water or marine salt to adjust the salinity, if needed. Add about 0. 25 tsp (1. 25 g) of baking soda per 1 US gal (3. 8 L) of water to increase the pH, if necessary.
Clean the sand more frequently if the tank tends to develop an unpleasant odor during the week.
Remove all plastic plants, toys, etc. , wipe them down with a rag soaked in a 3% bleach solution (available at pet supply stores), rinse them with clean water, and dry them with a clean towel. Remove and discard all the water and sand in the tank. Clean all the interior surfaces of the tank with the 3% bleach solution, rinse them thoroughly with clean water, and dry them completely with clean towels. Prepare the tank as you did for the original setup, using new sand and properly-prepared water. Make sure the water and the tank interior are within the appropriate temperature range.
