The devil crab is a fascinating semi-terrestrial species that is marked beautifully. The crabs are communal with their species and are an excellent choice for the nano aquarium. So if you are looking for something different to add to your terrarium setup, then it can be an interesting choice for you.
Usually, these brown land crabs are relatively larger terrestrial crabs and can be recommended even for new crab owners. Unfortunately, the ecology of these species is poorly researched. So many things are still unknown about these crabs. As a result, there is a lot of conflict about this fact.
Therefore, I decided to do my research on Zosimus aeneus. In this guide, I am discussing everything that is currently known about this species, including their interesting facts and how to care for them.
What is a devil crab?
A devil crab is the largest swimming crab that can be found in British coastal waters, with a carapace width of up to 100mm. Usually, their body is coated with short hairs, which can give the animal a velvety texture. So they are also called velvet crabs or velvet swimming crabs.
For UK fisheries, this is one of the major crabs that typically live in the North Sea. As well as the North Atlantic and the western parts of the Mediterranean Sea. Among the other species of crabs, velvet crabs are cryptic and typically inhabit humid rainforests that are close to small streams. As they are a social species, they do well in groups.
Scientific Classification of Toxic reef crab
- Scientific Name: Zosimus aeneus
- Kingdom: Animalia
- Phylum: Arthropoda
- Class: Malacostraca
- Order: Decapoda
- Suborder: Pleocyemata
- Family: Xanthidae
- Subfamily: Zosiminae
- Genus: Zosimus
Quick Fact of the Devil Crab
- Type: Terrestrial crabs
- Tank Size: 15 gallons
- Care Level: Very easy
- Breeding Level: Very difficult
- Optimal Temperature: 22–26°C
- Aqurium Type: Paludarium or Terrarium
- Water Type: Fresh and saltwater
- Diet: Omnivore
- Temperament: Semi Agressive
- Life Span: Upto 8 years
- Common Name: Velvet Crab, Velvet Swimming Crab, Devil Thai Crab, Brown Land Crab
Key Characteristics of the Devil Crab
Habitat
The beautiful and fascinating Zosimus aeneus crab is especially found on the east coast of Africa, on the southern islands and the Great Barrier Reef. Also, it occurs in the coastal regions of northern Australia. Besides, it occurs in the Cocos Islands. In their natural habitats, these unique creatures inhabit the landward fringe of the mangroves, borrowing the mud to hide. As well as being well-adapted to terrestrial habitats.
Behavior
The velvet land crab is a fully territorial species. In the wild, you can see them many kilometres away from the sea. To maintain an optimal moisture level, Zosimus aeneus constructs deep burrows. According to the research, it was found that their burrows can reach up to 2 meters below the soil surface. Besides, it terminates in a chamber at the level of the water table. However, an approximate volume of the sediment was calculated per burrow of 778 cm3. They dig such deep burrows because they require high moisture to breathe.
Feeding
The velvet crabs are primarily herbivores, preferring tender leaves, berries, flowers and fruits. However, they are also omnivores, which can allow them to feed on a wide variety of foods. They are best grown in captivity. So they require a good mix of meat and vegetation in captivity. Furthermore, their feeds should contain protein at a level of about 10-15% of their diet.
Breeding of Toxic reef crab
With several spawns per year, males mate with mature females. Their fertilization is internal. However, after 2-3 weeks, the eggs will hatch and must be released into the salt water for the larvae to survive. Though they can be found many kilometres inland, they must return to the ocean to spawn and release their planktonic larvae.
Longevity
In the wild, the maximum lifespan of this crab is 10 years. But in the aquarium, they get proper care and a good diet. So that they can live for up to 1 year more.
The devil/Toxic reef crab care
Tank size
If you want to house Zosimus aeneus, make sure to keep it in large tank setups. Because it is required for their potential growth. Hence, the appropriate tank size for these crabs is 15 gallons, which is the minimum. However, these crabs require a lot of surface area to roam.
Substrate
The tank should be filled with a good combination of moist sand or mud that they can burrow. So digging underground and from a cave, as well as the substrate, should always be kept moist enough.
Temperature
Velvet swimming crab temperatures range from anywhere between 71-79F. Usually, they prefer a warm and humid environment. However, if you decide to use a heating pad, cover the bottom of the tank. This can help crabs regulate their body temperature according to their needs.
Suitable tankmates
Though the brown land crab is semi-aggressive among the other species, it is still not fully peaceful and inoffensive. The male crabs are extremely likely to fight when hosing together in the tank. So that it can be ready to house multiple crabs in the tank. They should be placed in a tank along with other species of crabs.
Frequently Asked Questions
Which are the best foods to enjoy with these crabs?
The best foods that velvet crabs enjoy are vegetables like carrots, cucumbers, lettuce, broccoli, corn, spinach, peas and leafy greens. Besides, they like to eat foods such as apples, bananas, melon, mango and pearls.
Which food should I avoid feeding devil crab?
To keep your crabs healthy, you should avoid giving them foods such as acidic, salty, spicy, smoked, fried and flour.
How often should we change the food for the devil Thai crab?
Usually, you should change their food for 24 hours before removing it. But you must keep in mind that they store food in their burrows.
Do devil crabs need calcium?
Yes, they need it because it is a very crucial component of a brown land crab exoskeleton and their overall health and well-being whether you can find calcium in seeds, insects, broccoli, spinach, figs, oyster shells, or seaweed.
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