Red Claw Crab (Perisesarma Bidens): Ultimate Care Guide


Common NameRed Claw Crab
Scientific NamePerisesarma Bidens
OriginPacific Ocean / Asia
Temperature70-88°F
Water Parameters7.5 – 8.5 pH
Adult Sizeup to 4 inches
DietOmnivorous

Red Claw Crab Facts

  • Red Claw Crabs are very efficient climbers, and you will need to invest in a tank that has a good lid or you will have curious crabs exploring outside of their aquarium.
  • Red Claw Crabs need both land and water in their aquarium. If you are using the type of aquarium that doesn’t have shelves for them to get out of the water, then floating perches will work.

Red Claw Crab

Red Claw Crabs have primarily darkish colored bodies. These bland colors help them camouflage their environment in the wild. They sometimes have orange and yellow markings, but their most distinguishing features are their bright red claws and antennae eyes. They may be small, but Red Claw Crabs are very territorial.

Red Claw Crabs have a total of 10 legs. The first 8 legs are used for walking on the bottom of the ocean, and the last 2 legs are the claws. The Red Claw Crab uses its claws to help defend itself, climb, and eat.

Red Claw Crab (Perisesarma Bidens)
Red Claw Crab (Perisesarma Bidens)

Male and Female

Although similar in appearance, it is possible to distinguish the male Red Claw Crab from the female by just looking at them. The male has a more pointed underbody flap while the female has a more rounded underbody flap. The claws on the male Red Claw Crab tend to be larger and redder at full maturity.

Food and Diet

Red Claw Crabs are opportunistic feeders in the wild, and they survive on a mainly scavenged omnivorous diet. In captivity, they will accept most flake or pellet foods, and algae wafers. They will also accept and eat brine shrimp and mysis shrimp. It is a good idea to feed Red Claw Crabs at least twice a day to make sure they are getting their required nutrients. Red Claw Crabs are mostly bottom dwelling, and you will need to make sure that their food is sinking to the bottom of the tank for them to eat.

Size and Lifespan

When properly cared for, Red Claw Crabs can live up to 2.5 years in captivity. At full maturity, the Red Claw Crab can reach up to 4 inches in length including the legs. If you were to measure only the body of the crab, it would be closer to 2 to 2.5 inches in length.

How to Properly Hold a Red Claw Crab

Red Claw Crabs, much like other crustaceans, are a hands-off pet. It is not advised that you handle them at all. Unnecessary handling of Red Claw Crabs can lead to stress, and this can make your Red Claw Crabs unhealthy. However, if you are forced to hold a Red Claw Crab, you will want to keep in mind that it has claws. Red Claw Crabs use these claws to defend themselves, and they will use them if they feel threatened. It is best to pick them up from behind so that their claws are facing away from you.

Red Claw Crab Tank Requirements

Red Claw Crabs need to be kept in a minimum of a 10 gallon tank. Red Claw Crabs are a territorial species, and if you have the room for it, a bigger tank is ideal. Red Claw Crabs need both land and water in their aquarium. The ratio of land to water should be around 3 to 1 with the majority of their tank being water. An ideal aquarium for this setup would be a paludarium as it incorporates both terrestrial and aquatic elements.

Red Claw Crabs need to be kept at a temperature of 70F to 88F, so you will want to make sure that you choose a reliable heater for their aquarium. Red Claw Crabs also require slightly brackish water with a 7.5 to 8.5 pH.

The key to the health and happiness of Red Claw Crabs is keeping their aquarium well oxygenated and clean. You will also want to make sure that you have a secure lid for your tank as Red Claw Crabs are excellent climbers and will definitely climb out if given the opportunity.

Tank Setup for Red Claw Crab

When choosing decor for a Red Claw Crab setup, you will want to choose decor that mimics their natural environment as closely as possible. A fine sandy substrate is a good choice for a Red Claw Crab aquarium. The sand allows them to get around without problem, and is easy for them to dig around in. It is important to remember to give them some land or decor that they can rest on above the water. If you are setting Red Claw Crab up in an aquarium that doesn’t have shelving built in for this, then floating perches are a great alternative.

Driftwood and rocks make for great decor for a Red Claw Crab tank. They will find and use places to hide and destress when they feel they are threatened. Having a safe place to destress is very important to a crab. A stressed Crab is more prone to getting an illness.

Real plants can be added to an aquarium containing Red Claw Crabs, but they are well known for their plant destroying nature. They will uproot, and shred plants as they dig through the substrate. Some owners of Red Claw Crabs use and recommend silk plants, but they will most likely mess with those too.

Red Claw Crab Habitat

In the wild, Red Claw Crabs live in brackish water. They spend the majority of their time in the shallow rivers, and murky swamp estuaries that meet the sea. They need brackish water that is both freshwater and saltwater. This environment provides them with plenty of food and places to hide from predators.

Do Red Claw Crabs Need Land?

Red Claw Crabs need their habitat to be 3 parts water for every 1 part of land. Depending on the type of tank you are using to house your Red Claw Crab, you may need to purchase floating perches for them to rest on. There are some tanks that you can purchase that are specifically designed to give the occupant land and water, but choose carefully as the Red Claw Crab is an excellent climber and can easily escape a tank without a lid.

Do Red Claw Crabs Need Brackish Water?

Red Claw Crabs need brackish water in their aquarium. Brackish water is water that has more salinity than freshwater, but not enough to be considered saltwater. The water for a Red Claw Crab would need to have 1 tablespoon of salt per gallon. It is important for the health of the Red Claw Crab that its aquarium receives regular water changes, and that you establish a regular cleaning routine. A 10 percent water change every week is sufficient to keep their water from getting unhealthy.

Do Red Claw Crab Need Freshwater?

Red Claw Crabs can survive in a freshwater tank, but they will never reach their full growth or aging potential. They require brackish water. Brackish water is water that has salt in it. Brackish water has less salt than saltwater, but more salt than freshwater.

Red Claw Crab Breeding

When female Red Claw Crabs are ready to spawn, you will be able to visually see her carrying her eggs under her tail. She will carry her cluster of eggs for 3 weeks before they are ready. You will be able to see the eggs change from a reddish color to a gray. When the eggs turn gray, you will want to move her to the breeding tank for the eggs to hatch. A dedicated breeding tank will give the sensitive Red Claw Crab young a chance to survive. Once the Red Claw Crab young have hatched, you will be able to feed them. Artemia is a good choice, and it is best to offer them food 3 to 5 times a day to make sure that they are getting the right nutrition.

How Do Red Claw Crabs Breed?

There is not a lot known about the specific rituals of Red Claw Crab breeding, but it rarely does occur in captivity. It is possible to get a breeding pair and a clutch of eggs, but it can be tough to replicate the conditions the young Red Claw Crabs would need to grow and thrive.

It has been said that the male Red Claw Crab will choose the female he wants to mate with and use his claws to flip her over and pin her down. Parent Red Claw Crabs provide no care to their offspring, and will even eat them if given the chance.

Red Claw Crab Disease

Red Claw Crabs are resistant to disease. They have even been known to feast on the disease infested carcasses of fish with no problem. Red Claw Crabs can still get bacterial and parasitic infections. It is important for the health and happiness of your Red Claw Crabs that you establish a regular water changing routine, and you monitor their water parameters often so that you can correct any issues before they become a problem.

Red Claw Crab Molting

Red Claw Crabs have what is called an exoskeleton. This means that in order to grow larger they have to molt. Molting is the process in which the Red Claw Crab buries itself and sheds its exoskeleton. Much like a human outgrows their clothing, crabs outgrow their exoskeleton, and they will shed it as they outgrow it.

How to Tell if the Red Claw Crab is Dead or Molting

The only sure way to be able to tell if your Red Claw Crab is dead or just molting is to observe it. It can take Red Claw Crabs a long time to molt. This process could take months. If you notice mold growing on the body of the Red Claw Crab, the chances are that it is dead and not molting.

How Long Does it Take for Red Claw Crab to Molt?

It can take a long time for Red Claw Crabs to molt. This often leads to people mistaking them for dead. It is important to know that it takes around 2 to 3 months or sometimes even longer for the Red Claw Crab to shed its exoskeleton.

Red Claw Crab Tank Mates

Due to the brackish water in which Red Claw Crabs have to be kept, your choice for tank mates is limited. You will want to make sure that you are not putting your Red Claw Crabs into an aquarium with fish that consider them food, but Red Claw Crabs would do best with some types of mollies, flagfish, and gobies.

Red Claw Crab and Betta

It is not a good idea to house Red Claw Crab fish with Betta. Red Claw Crabs will harass and pinch at the slow moving Bettas.

Red Claw Crab and Snails

Red Claw Crabs should not be housed with snails as they will see them as food and go after them.

Red Claw Crab and CIchlids

It is not a good idea to house Red Claw Crabs with Cichlids. Both will go after one another if given the chance.

Red Claw Crab and Ghost Shrimp

Red Claw Crabs can be housed with most kinds of shrimps that can tolerate the same water parameters.

Red Claw Crab and African Dart Frog

Red Claw Crabs can be housed with African Dart Frogs, but it is important to know that the Red Claw Crabs will eat the frogs and the young of the frogs during their various life stages if they are given the chance.

Where Can I Purchase Red Claw Crab?

Red Claw Crabs can be purchased in pet stores and online for around $4 per crab. You will want to make sure that you are purchasing from a reputable source to ensure that you are getting healthy, quality crabs.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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