The marble crab Metasesarma obesum is a small land crab that makes its home in the Indo-West Pacific, where it occurs in large populations, sometimes even on small islands without any freshwater source. The marble crab gets its name from the marbled pattern on a light brown background that the animals often display. Basically, however, it is extremely variable in color, there are also animals with darker carapace. Common to all of them is the dark brown facial mask and the lighter, thick as if inflated claws.
The very social Metasesarma obesum belongs to the mangrove crabs. The sociable small crabs with a carapace width of only 2.5-3 cm can be kept in a group of three animals already in smaller terrariums from 40 cm. Here you should make sure that the group has more females than males. The males can be easily identified by their abdominal flap: It tapers to a v-shape in the front, whereas the abdominal flap of the females has the shape of an upside-down U.
The breeding of Metasesarma obesum has not yet been successful in the hobby. The females carry a very large number of very small eggs and release floating larvae into the sea after the end of the gestation period, which need seawater or brackish water to develop into crabs.
In the aquaterrarium Metasesarma obesum does not need a large water section, a shallow bowl of fresh water is sufficient. If you like, you can also offer a shallow bowl with seawater. Now and then the animals sit with their legs in the water, but basically they are happy and often on land and use all possibilities to climb.
Accordingly, the terrarium should be furnished varied and offer the animals climbing opportunities and also hiding places. Cork bark, twigs, roots and stones are gladly accepted. They also like to burrow, an 8-10 cm high layer of terrarium humus is gratefully accepted. The substrate should be kept permanently moist, so a sufficiently high humidity is also guaranteed. Since Metasesarma obesum does not attack plants, the terrarium can be nicely planted and designed.
A heating is not necessary, the marble crab prefers air temperatures between 20 and 30 °C, room temperature or the warming by the terrarium lighting is thus completely sufficient.
The terrarium must be tightly closed, Metasesarma obesum is a curious animal and likes to wander.
Metasesarma obesum is a predominantly carnivorous crab, so it prefers meaty food: protein food, frozen food, unseasoned raw fish, freeze-dried insects and so on. Of course, it also gladly accepts special food for carnivorous crabs. Brown fall foliage should always be in the terrarium, although the animals do not often nibble on it, they do like to take the foliage as a hiding place. Also live food in the form of white isopods or springtails is gladly hunted and eaten. These small animals can live permanently in the aquaterrarium, they take care of food remains and serve as a food source at the same time
The marble crab should not be socialized, it needs a species terrarium. Since this is a very social group animal, it should not be kept alone. In good conditions Metasesarma obesum can live for several years.