Cardisoma Armatum (Tri-colour crab)
Appearance: Up to 15cm. Colours are red, blue and white.
Sexing: Males are brightly coloured compared to females. Colours will fade when getting older. Males have larger claws which are uneven in size. Female claws are even in size and smaller.
Female abdomen plastron is round and almost covers the entire belly. Male abdomen plastron is narrow and has more a pointy shape.
Life span: At least 12 years.
Size: 10 to 20cm.
Sexually mature: From 5cm wide.
Gestation: 2 to 3 weeks.
Character: Aggressive towards the same species and basically everything they can get hold of with their claws. They like to spend hours or days resting on a piece of wood over the water of on land. They like to dig. Knee deep in the water overlooking the scene and still being able to breath is a favorite as well.
They usually do not eat aquarium plants but will break them while walking.
They like to be brushed over the carapace with a toothbrush and even the claws when they trust the situation. These crabs can learn to recognize the care taker and even be fed with tweezers or by hand(be very careful).
Tank setup: The most appropriate tank setup is 1/3 water and 2/3 land.
In their natural habitat they like to dig burrows. Use sand or terrarium humus for the land part and add stones, wood, leaves and hiding places. Sand and/or gravel can be used in the water part. Although they spend a lot of time on land they need access to water in order to keep their gills moist and to molt easier.
They can not extract oxygen from the water but breath via their gills so it's important for them to be able to climb out of the water. These crabs can drown!
Waterconditions: Temperature 20 tot 28ºC. Most ideal temperature is 24-25ºC.
Feeding: Cardisoma armatum is an omnivore, and eats leaves, plants, pellets for crayfish and shrimp , food for bottom fish, flake food, all kinds of fruit and vegetables like peas, lettuce, cucumber, apple, zucchini, pear, banana, grapes, tomatoes, Brussels sprouts. fish, mussel meat, insect larvae, spirulina tablets and insects.
They will also eat frozen food like cyclops, brine shrimp. For adding calcium you can use broken egg shelves or calcium in sticks.
Breeding: Breeding can only be done in brackish water. After about 3 weeks larvae are released in the sea. After several growth stages they will return to the shore are miniture crabs. Breeding in captivity is hard because usually only males are imported.
Tank mates: Shrimp, snails(small ones will be eate). Guppy, neons. Do not put fish in the tank that live on the bottom.
Copyright photos: © Eurofish(left), Xciber(right)