The red devil crab, aka red vampire crab, is a beautiful craft of nature and a common name in the aquarium hobby. This little crab lives peacefully with its own species and thrives in vivariums or paludariums.
Caring for this crab is easier than you think. However, there are some exceptional requirements you should keep in mind to keep them thriving.
Quick overview of red devil crab
| Names | Red devil crab, red arm/red vampire crab, red devil vampire crab, red devil moon crab, red devil krab, demonic crab, red devil freshwater crab, red apple vampire crab |
| Scientific name | Geosesarma hagen |
| Care level | Easy |
| Habitat type | Freshwater paludarium |
| Diet | Omnivore |
| Sleeping nature | Nocturnal |
| Optimal temperature | 24-28°C (75-82°F) |
| Size | Up to 7 cm |
| Lifespan | Up to 2 years |
| Breeding | Easy |
| Color | Orange, red, and dark-brown |
Red devil crab habitat habitat
Red devil crabs live on land, usually in rainforests near freshwater sources such as rivers and lakes. They are endemic to Java, Indonesia, meaning they can only be found there.
Some facts about red devil freshwater crab
Appearance (demonic crab)
The red devil crabs have a square-shaped, wide carapace with a red or orange color on it. The other part of the body is dark except for the eyes and claws. They have glowing yellow eyes and distinguished red-to-orange claws, which are the most attractive part of their body.
A fully grown red devil crab can reach up to 7 cm.
The males have larger claws with a narrow plate, while the females have a broad plate, and their claws are comparatively smaller. The young crabs are transparent, and they become colored as they grow up.
Behavior
Red devil crabs are considered semi-aggressive crabs, especially because they are territorial with other geosamma species and invertebrates. With a lot of space, a group of red devil crabs will do well in a paludarium.
Highly nocturnal
Red devil crabs are likely to hide from the light; they burrow and hide to protect themselves during the day. A difference between them and other terrestrial crabs is that they can’t burrow too deep. Compared to the red devil crab, other crabs are more visible during the daytime.
There is a lower chance your crabs are caught in their natural habitat; if that is the case, they will hide more and be shy compared to a captive breed.
A fun fact is that all of the Geosesarma species are very colorful, which makes it too easy to give an eye-catching name like the orchid vampire crab or the rainbow vampire crab. This helps traders attract customers with an attractive name.
Red devil crab care
Tank setup for red vampire crabs/red devil crab tank setup
Size
To avoid territorial disputes, you should start with a 20-gallon tank for 8 to 10 crabs; a 25-gallon tank will be perfect for a dozen red devil crabs. For 2 to 3 crabs, a 5-gallon tank is enough. Don’t forget about the lid if you don’t want your crab to vanish from the tank and appear in your room; this has happened to many people.
Substrate (red devil vampire crabs)
Choose a substrate that holds moisture, but the substrate should not contain a large amount of sand. 20 to 30 percent sand is preferable, and coco fiber should be the main part of the substrate.
The tank will be divided into two parts—land and water. Finish the setup with rocks, caves, gravel, live plants, moss, ferns, and wood.
Temperature and humidity (red devil vampire crab)
The temperature should be between 24 and 28°C (75-82°F) with a humidity of 70 to 80%. Use related equipment like a thermometer and hygrometer.
What can red devil crabs eat
All of the crabs are considered to be omnivorous. But some of them show carnivorous behavior, such as the red spotted coral crab and the decorator arrow crab; the red devil crab is one of them. Thus, give preference to meaty foods over fruits and vegetables.
Red devil crabs rely on small insects like woodlice, detritus, algae, and decomposing plants and animal matter in their natural habitat.
Provide flakes, pellets, and commercial food made for crabs. Also provide bloodworms, brine shrimp, crickets, frozen foods, roaches, or fruit flies. They may let the food rot sometimes; that’s normal. However, clean up rotten food or leftovers before they bring mites.
Molting of geosesarma hagen
They go through several moltings during their lifetime to grow in size and recover lost limbs. During that time, you shouldn’t disturb the crab, and if other crabs or frogs do, you should keep the crab in isolation and feed it calcium-rich foods such as cuttlebone, broccoli, kale, and spinach. Boiled vegetables are preferable.
How will you know that a red devil crab is about to molt? Well, they molt every one to two months, so you will know when they’ll molt by their previous molt. Young crabs molt more frequently.
Before molting, they will hide more than usual and will be lazy. Eating more than usual can also be a sign of molting.
Which tankmates are suitable for red devil crabs?
If you keep red vampire crabs in a group (which is obvious), there should be more females than males. Males are likely to fight over territory and be aggressive to each other. So keeping more females decreases the chance of fighting and increases the chance of breeding. 2 to 3 females against one male would be a good ratio.
Keep fish that have a high speed, are peaceful, are small but not too small, and share the same condition. For example, chili rasboras and amber tetras.
Small geckos and dart frogs can also be a good option as red devil crab tank mates.
Young red devil crabs stay closer to water to avoid predators; however, in captivity, this behavior should be taken into consideration. After hatching the eggs, the mother leaves the baby crabs in the water, where they will live for several months. If you keep fish with them, they will eat all of the babies.
Breeding
Red devil crabs are generally easy to breed. Most hobbyists succeed in breeding this and there is no extra requirement for breeding.
After providing the required conditions, if they do not breed, you should create a mini paludarium for two crabs. Take a male and a female and bring them to that mini tank. This way, they should mate or else try different combinations.
The female releases eggs in the water, and each crab releases 12 to 24 eggs, depending on the female’s capability and the environment. Incubation lasts for 1 to 2 months, and they have no larval stage. After hatching a fully formed crab, the female will carry them for some time.
Frequently asked questions
Red devil crab vs vampire crab
The red devil crab is actually a type of vampire crab—specifically, Geosesarma hagen. The term “vampire crab” is used for several colorful Geosesarma species. While all vampire crabs share similar care needs and behaviors, the red devil crab stands out with its bright red claws and glowing eyes, making it one of the most striking and popular varieties in the hobby.
Red devil crab edible
Red devil crabs are not considered edible. They’re tiny, only growing up to 7 cm, and are kept solely for ornamental purposes in paludariums. Their bright colors and peaceful nature make them great pets, but they’re not farmed or consumed for food.
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