Harlequin crab - Cardisoma armatum

The colorful harlequin crab Cardisoma armatum displays an unusual color combination. While its dorsal carapace is blue, it has white claw arms and claws and bright orange-red to red walking legs. However, Cardisoma armatum stands out not only because of its coloration, but also because of its size. With a carapace diameter of 12 to 15 cm it already belongs to the large land crabs. It comes to us from the West African region.

The females of Cardisoma armatum carry several hundred very small eggs under their U-shaped abdominal flap (the abdominal flap of the males is shaped like a narrow V). After several weeks of gestation, the female releases free-swimming larvae into the sea. There they develop over several larval stages into finished small crabs, which then leave the sea again and move on to land life. In the hobby, no one has yet succeeded in reproducing the harlequin crab.

As a land crab, the Harlequin crab is mainly not found in water, but its size requires a "real" water part of about 40% of the aquaterrarium area, in which it can be completely submerged for molting - a water bowl would be too shallow. Water values are practically irrelevant here, brackish water is also possible.

Since the Harlequin Crab is also quite aggressive within the species and very territorial, we recommend keeping them individually. An aquaterrarium with an edge length of 100 cm is sufficient. Only in really large aqua-terrariums with an edge length of more than 120 cm and an extremely well structured setup of wood and stones, which offers the animals many Hiding places and escape possibilities, the attitude of a pair is possible. Then you should also plan two separate water parts.
As substrate for the land part, which should be permanently moist, we recommend terrarium humus, which should be deep enough for the crabs to dig living caves.
For harlequin crabs the temperature must be between 25 and 28 °C.

Harlequin crabs are very nimble and skilled climbers. Especially young crabs can even climb up the silicone seams. Since Cardisoma armatum are very large and also strong crabs, the lid of the aquaterrarium should not only rest on, but possibly be weighted down. If you want to filter the water part, you should think about an airlift for this purpose - electric cables are easy for the strong claws of the harlequin crabs.

Cardisoma armatum can besocialized quite well with small fish and dwarf shrimps, which can be placed in the water section - sufficiently large and with the values matching the stocking. However, you have to take into account that the harlequin crab might go hunting. Well reproducing snails are an ideal additional stock, which can serve as a permanent live food source.

The Harlequin Crab prefers a well-balanced diet consisting of both animal and vegetable matter. Foliage is eaten with great pleasure, but Cardisoma armatum also likes fruit, spinach and nettle, vegetables, freeze-dried food such as stream fleas or insects, smelts and commercial frozen food and uncooked fish. Ready-made food for crabs is of course also eaten with pleasure.

Our food recommendation: Crabs in the wild usually have a varied diet. Most species are omnivorous, and with the Natureholic Crab Feed Sticks we have taken this preference into account. They contain biologically balanced animal and vegetable components, which are also part of the natural food spectrum of omnivorous crabs in the wild in this or a similar way. The valuable ingredients of NatureHolic Crab Feed support the moulting, digestion, growth and reproduction of your crabs in a completely natural way.

Our plant recommendation: For planting, use marsh plants, which are plants that are rooted in soil that is very wet or even submerged, but whose flowers and leaves are usually all or partially in the airspace and can be seen above the water surface. Thus, marsh plants are usually found on and in lakes and streams, but also on and in garden ponds or other bodies of water that provide them with a wet substrate, but still leave room for flowers and leaves to show outward.

Expert Tip: We recommend NatureHolic 3 Phase Liquid when keeping invertebrates. The care set offers the best all-round protection for your invertebrates. It ensures optimal conditions for successful breeding and keeping.