Cardisoma armatum “Harlequin Crab”

Cardisoma armatum – Crustacean farming can be so colorful

The Cardisoma armatumbetter known as the harlequin crab, is one of the most impressive crabs in the terrarium hobby. Its bright blue shell, red claws and orange rump make it a real eye-catcher. It is precisely this variety of colors that gives it the name “harlequin crab”, as it is reminiscent of a colorful costume. Because it is active during the day, it is also wonderful to observe – which makes it interesting not only for professionals, but also for beginners.

The animals originally come from West Africa, more precisely from coastal regions with moist, warm habitats. There they live in sandy soils in which they dig deep burrows. It is therefore important to create similar conditions in the terrarium. A tank measuring 60 × 40 cm or more and filled with at least 10-15 cm of diggable substrate is ideal. A mixture of desert sand and forest humus is particularly suitable as it is both stable and retains moisture.

To make the crab feel safe and comfortable, you should also provide cork tubes, roots and moss. These materials not only serve as a place of retreat, but also as design elements. As Cardisoma armatum is very curious, it likes to explore its territory and also moves smaller items of furniture around. Over time, this creates an individual habitat that the animal itself helps to shape.

Although it is a land crab, it always needs access to water. A shallow water dish with slightly salted water is perfectly adequate. Alternatively, you can also set up an aquaterrarium with land and water sections, as long as both areas are safely accessible. It is important to pay attention to hygiene and change the water regularly.

Temperatures between 24 and 28 °C during the day and around 22 °C at night correspond to natural conditions. A humidity of between 70 and 80 % should also be maintained at all times. We recommend using an LED or UVB daylight lamp so that the crab’s colors are shown to their best advantage and its day-night rhythm remains stable.

Cardisoma armatum is highly territorial, which is why you should always keep them individually. Several animals in the same terrarium almost always lead to fights. However, it is ideally suited to being kept individually as it is very active and exciting to watch.

It is a real omnivore when it comes to food: vegetables, leaves, fish flakes, protein food and dried insects are all part of the diet. A cuttlefish shell provides the necessary calcium supply and helps to build up the shell, especially after moulting.

If you are looking for a colorful, lively and interesting animal that you can observe during the day, the harlequin crab is a perfect choice. It is robust, easy to care for and brings a tropical flair to any living room terrarium.