Crab Red Devil – Miniature Demon

Recognizing the names of some animals, one is inevitably surprised at human fantasy. For example, with the phrase “red devil” something large and aggressive is drawn in the imagination, but it turns out that such a frightening name was given to a miniature crab from Southeast Asia. We invite you to get to know these interesting animals better.

General information

The Red Devil Crab (Geosesarma Hagen) is a freshwater crustacean from the Sesarmidae family. The animal received its name for the contrasting combination of a dark body and bright orange limbs.

The small size of crabs (up to 2 cm) and unpretentious care made them popular pets. The most important thing to remember is that this species is terrestrial, and it is absolutely impossible to keep it exclusively in water.

The character of the crab is peaceful, it can be settled together with relatives and even with small fish. And getting offspring from these exotic animals will not be difficult.


Outwardly, the Red Devil does not differ at all from other crabs. The body is rounded, covered with a strong carapace (carapace) to protect against enemies. The abdomen (abdomen) is short, symmetrical, and bent under the jaw. Since crabs are a Decapod crustacean, they have 5 pairs of walking legs, the front of which has evolved into pincers for holding and moving food into the mouth, equipped with several pairs of jaws.

The sense organs are represented by eyes located on movable stems and short antennae.

The main color of the body and walking legs is from dark purple to almost black. Carapace and claws are colored bright red or orange. The eyes are yellowish.

Life expectancy at home is 2-3 years.


In its natural environment, the Red Devil crab is found on the island of Java (Indonesia). Despite the fact that crabs are predominantly terrestrial, they do not completely lose contact with water. Mostly they can be found in swampy areas or near small streams, on the banks of which they dig holes for themselves.

Care and maintenance

To keep the crabs of the Red Devils, it is necessary to prepare a spacious aqua terrarium. The recommended volume is from 50 liters per group of individuals (5-6 pcs). It is desirable that the bottom area be maximized. The ratio of water to land should be 50/50. The land part is created from a mixture of peat, coconut substrate, and sphagnum moss. Swamp aquarium plants can be planted in a moist substrate: anubias, cryptocorynes, bucephalandras, echinodorus, etc., because the crab’s Red devils do not damage them.

Water is necessary for crabs during molting, its level can be small – 15-20 cm. It is advisable to install a small filter to maintain the purity of the water or if you plan to additionally keep fish in it. It is recommended to make some cover in the water.

It is necessary that the aqua terrarium has a tight cover. Crabs Red Devils have an amazing ability to escape even into small crevices. For the same reason, it is best to cover all technological holes with a mesh.

It is very important to recreate a special microclimate in the crab home. The optimum temperature of water and air is 24-26 ° C and 25-28 ° C, respectively. For the comfortable existence of Red Devils crabs, it is very important to maintain almost 100% humidity in the aqua terrarium. This can be achieved by regular spraying, using heating mats or cords under the container (humidity will increase due to the evaporation of water), or using an ultrasonic fog machine. It is optimal that the water is close to neutral (pH = 7.0-7.5) and has an average hardness (GH = 10-20).

Water must be regularly (once a week) replaced with fresh water along with a soil siphon. It is not recommended to top up water directly from the tap, as it may contain compounds hazardous to crabs, such as chlorine and heavy metals. Tetra Crusta AquaSafe Conditioner will help you instantly make the water safe and avoid the difficulty of settling.

The hard chitinous cover of crustaceans (including crabs) does not allow it to grow in size, so animals regularly shed it in order to be able to grow. This process is called molting. The younger the crab, the more often the skin changes. Molting is a big stress for the Red Devil crab, as it requires a lot of energy. Before molting, the crab stops eating and tries to hide. The growth of the animal takes place until the new shell has hardened – at this time the crustaceans are very vulnerable. The discarded cover should not be removed from the aqua terrarium; the crab will eat it to replace the loss of nutrients. In the process of molting, the restoration of lost limbs – legs, claws also occurs.


Most often, Red Devils crabs are kept in the specific aqua terrarium in small groups of 4-6 individuals with a predominance of females. It is extremely interesting to watch them, and adding additional neighbors is not always advisable.

If desired and possible, small ornamental fish, for example, guppies, as well as snails or shrimps, can be placed in the water part of the dwelling. For the latter, crabs can try to hunt, but usually, nothing comes of it.

Feeding the crab red devil

Crab The Red Devil is an omnivorous creature. In nature, they eat whatever they can find: fallen leaves and other decaying debris, worms, insects, mollusks.

At home, it is better to choose a quality dry crustacean food, such as Tetra Crusta, as a basic food. They are fully balanced and contain sources of animal and plant proteins and vitamins necessary for health. Tetra WaferMix aquarium catfish tablets are a good alternative.

Remember to feed your crabs with slices of soft vegetables, fruits, and berries. You can use cucumber, tomato, banana, peach, strawberry, etc. It is useful to put dried tree leaves (oak, Indian almonds) into the aqua terrarium. They will not only become an excellent decoration but also serve as an additional source of food for crabs.

You don’t need to feed the Red Devils Crabs every day, it is enough to do it 2-3 times a week. Overfeeding is harmful to the health of these invertebrates because it can provoke molt, for which the crustacean is not yet ready.

To feed the crabs, it is best to have a small plate that holds the food pieces. Additionally, they can be sprinkled or dipped in calcium vitamins such as Tetra ReptoCal.

Reproduction and breeding

Gender differences in the Red Devils crabs are pronounced. If you look at their abdomen (abdomen), then in males it will be narrow, and in females wide – this is a device for carrying eggs. Crabs become pubertal at the age of 6-8 months.

In the presence of a pair and suitable conditions in the aqua terrarium, breeding crabs at home will not take long. A distinctive feature of these terrestrial crustaceans is the absence of a free-swimming larva. All development takes place in the egg, and already fully formed individuals about 1 mm long are born. The fecundity of a female can be 50-60 eggs. Red devils crabs, typical for adults, begin to acquire color after several molts.

Alice White

Written by Alice White

Alice White, a devoted pet lover and writer, has turned her boundless affection for animals into a fulfilling career. Originally dreaming of wildlife, her limited scientific background led her to specialize in animal literature. Now she happily spends her days researching and writing about various creatures, living her dream.

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