Red Claw Crab: All the Information You Need

Have you ever thought to buy some freshwater crabs for your tank? Well, that’s great because today we are going to talk about a crab species, which is red claw crab. Maybe after reading this article you will immediately head to the fish store and get yourself some red claw crabs for your aquarium. We will try to cover all the spheres referring to these species. So continue reading for all the information about red claw crabs.

red claw crab

General information

Red claw crab is also known as Perisesarma bidens, mini crab, Sesarma bidens or sesarma moeschi. These species are often mistaken for freshwater crabs but they feel perfect in brackish water. These species can naturally be found in Asia. They live in a tropical temperature areas with shallow water and a sandy ground. Red claw crab can grow maximum up to 10 cm and are relatively smaller than most other aquarium crab species. That is why they are also known as mini crab. You can differentiate male crabs from female by the red claws which are larger in males and the underside of male shell is pointier while in females’ rounder. Usually these crabs have a lifespan of around 2 years.

Aquarium requirements

You have to keep them at least in a 60 cm paludarium with land. The salt of the water in the tank needs to be around 1.005. You should regularly change the water and it should be filtered, heated and cycled. Also, you need to keep the aquarium similar to their natural habitat. The land area in the tank should be sandy and you can add some rocks and plants as well. The crabs should have many hiding places. Especially when they are molting they need a place to hide.

Also, you should be careful with red claw crab as they tend to escape the tank. To prevent this you need to cover all the possible areas from where the crabs can escape. As they dehydrate pretty fast, their escape can have sad results.

Feeding red claw crabs

These crabs love to hunt actively but they are not very strict carnivores. You should feed your red claw crabs with plenty of protein such as bloodworms or uncooked fish in small pieces. The diet of red claw crabs should also include a lot of vegetables, such as spinach, pees and leafy greens. You can feed you red claw crabs with regular fish food as well, such as commercial crab food and algae pellets.

What tankmates should you get for red claw crabs?

As red claw crabs are territorial it is not recommended to keep many males in one tank as they may start a territorial war and even can kill each other. For instance, in a 60 cm paludarium you can keep one male and up to 3 female crabs. It is way easier to keep red claw crabs in a one species setup, but if you find that your tank is large enough for more species then you can get some tankmates.

But notice that crabs can hurt some fish, especially the slow ones. Tankmates should stand low end brackish water and should not be bottom dwellers.

The breeding of red claw crab

Actually the mating of red claw crabs is a very difficult task and it is almost impossible to do in a tank. Red claw crabs start their lives as larvae and will probably not survive in a tank. Females carry eggs but the eggs again probably will not hatch in a tank. So the breeding of red claw crab is pretty much possible only in their natural habitat.

What behavior do red claw crabs have?

It is really fun to keep red claw crabs as they are very fun to watch. Though they spent a lot of time hiding. But when they come out they can be very entertaining. Owners with a soil substrate will notice that these crabs like to show their natural scavenging behavior. When they meet a tankmate, be it a fish or another crab, they become defensive and raise their claws in order to scare the intruder.

Some hobbyists say that their red claw crabs lose fear of them after a while. But still if you will need to take the crab to hand do not forget that they can pinch you.

Where to buy red claw crabs?

If you want to get some red claw crabs you can find them in your local fish store. Also you can get these crabs online. Some people complain that they could not find red claw crabs in any aquarium stores. But anyways in this case you can always choose the online shopping option.

Overall specifications

  • Origin – Asia
  • Other names – Perisesarma bidens, mini crab, Sesarma bidens or sesarma moeschi
  • Tank size – at least 60cm paludarium
  • Water type – Brackish water
  • Salt of water – should be around 1.005
  • Temperature – 72-82 F degrees
  • Breeding – Egg hatching and larvae, but almost impossible to do it at home
  • pH level – 7,5-8,5
  • Diet – Omnivore
  • Temperament – Aggressive

So, we can say that keeping red claw crabs can be both simple and challenging. Even though some of the difficulties red claw crabs are very fun to keep. The most difficult parts of keeping these crabs is the tank setup and the breeding. The tank has specific requirements which should be mimicking the natural habitat of red claw crabs. And if you will have a tank with all the required setups there will not be any other difficulties. As for the breeding, it is better not to think about it at all, as most probably you will not have any results. So if you have decided to get a paludarium of red claw crab, then good luck and do not forget to have all the required factors for them to be happy and healthy.

4 thoughts on “Red Claw Crab: All the Information You Need”

  1. I just started caring for red claw crabs a few days ago, and the branches that I have in the tank for climbing and getting O2 are covered in a sort of clear but milky substance with tiny silver….eggs? I’m guessing one of my crabs mated at the aquarium I bought them from. Are we sure these eggs won’t hatch? AHHH

    • Hello, I am new to keeping red claw crabs as well though I have other aquariums and other types of crabs. I think what you could have been experiencing was more sap from the branches leeching out. Aquarium branches etc can look milky and pretty gross for the first few weeks in a tank. I try to pre-soak them for a long time before I put them in the tank and I will take them out and spray them down with hot water on occasion those first few weeks..


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