PERISESARMA CARE GUIDE
Author: Albomita
Perisesarma bidens is a small, colourful crab species native to coastal and estuarine habitats across Asia. It boasts one of the widest ranges of any crab in the pet trade, with natural populations recorded in brackish mangroves from West India, Bangladesh, and Taiwan to southern Japan. Due to its adaptability and striking red claws, P. bidens has become arguably the most commonly sold true crab species in the global aquarium market. It is so widespread that it is often found in big chain pet stores.
However, a common misconception in the trade is the labelling of Perisesarma bidens as a freshwater species. In reality, this species thrives in brackish environments, and long-term health issues can occur when they are kept in pure freshwater. Responsible keepers should ensure proper salinity and brackish water conditions to provide the best care possible. These crabs are very commonly sold as Vampire Crabs by mistake, so be aware of that if you are looking to buy either species, as they are very different crabs with different care requirements.
Members of the species
Conservation level
Not evaluated – This species is abundant in the wild and commonly bred or collected for trade, though habitat degradation in mangrove zones may pose future risks.
Care level
Dark Method: Beginner, Suitable for those who follow the "dark method" of keeping crabs.
Fresh (Display Method): Beginner These crabs are easy to maintain even in aesthetic enclosures, as long as environmental needs are met.
The Dark vs Love Methods Explained
Enclosure and Environment
Perisesarma Bidens, or the Red Claw Crab, is a primarily aquatic species. It is not fully aquatic and needs surface access. This can be given in the form of a landing as seen in turtle tanks, driftwood sticking out of the water, or a large rock. They are not too picky about their aquarium, if it would work for a snail or fish, it will likely work for them too.
Temperature: 27°C / 80°F
Minimum Tank Size: 10 gallons per crab
Salinity: 1.005 SG (brackish) – Achieved by mixing marine salt into dechlorinated water
Water Changes: Every 1–2 weeks, depending on bio-load
Lighting: Provide a natural day-night cycle.
Substrate
Crabs benefit from being able to dig and sift, though P. bidens is not especially picky.
Best Options:
Fine sand
Muddy soil blends (aquarium-safe)
Soft, small-grain gravel
While they may adapt to rougher substrates, finer materials support more natural behaviours.
Cohabitation
Perisesarma bidens is moderately territorial. With proper space and hides, small groups can thrive.
Ideal Groups: Male/Female/Female (1m/2f) trio
Minimum for Pairing: A 20-gallon tank is recommended for a stable pair
Cautions: Always provide plenty of hiding spots to avoid conflicts, especially during molting
Diet
These crabs are omnivorous, with a preference for protein-rich foods. A varied diet helps promote healthy growth, shell strength, and natural colouration.
Staples:
Small invertebrates (frozen or live bloodworms, brine shrimp, tiny snails)
Soft fish foods (sinking pellets, wafers)
Vegetables:
Soft vegetables
Data Source
The information in this guide was kindly researched and provided by the team at Crustacean Council.