Tropical Crabs
Three Of The Best Known Tropical Crabs
Unlike most of their salt relatives who live in temperate or cold climates, tropical crabs can be found in fresh water, brackish water, and on land. Some, like the coconut crab, spend virtually all of their time on land. A few terrestrial species spend some time in the water when mating, and others live almost exclusively in the water.
Most freshwater crabs are tropical crabs and are found in many different countries located in the tropical and subtropical regions. Freshwater tropical crabs are exceptionally valuable as scavengers, although that can be said for other types of crabs as well. Freshwater tropical crabs can be valuable in a freshwater aquarium due to their scavenging habits, as long as they are a species that won't give fish companions problems. Like their saltwater cousins, many species of freshwater tropical crabs are caught by humans for use as a vital source of protein in areas where sources of protein are scarce. There are over 850 species of freshwater and terrestrial crabs in the tropics, divided into two main categories, New World crabs and Old World crabs.
The Red-clawed Crab - On of the favorite tropical crabs for an aquarium is the Red-clawed crab. The Red-clawed crab's natural habitat is hard or brackish water, so other residents of the aquarium need to be those who can live under the same conditions. The Red-clawed crab is not particularly large, measuring just under 3 inches. It requires access to dry land where it will spend part of its time. It will eat a diet of dried fruit and vegetables in addition to helping keep the tank clean.
The Fiddler Crab - Another aquarium favorite among the tropical crabs is the Fiddler crab. The Fiddler crab is somewhat smaller than the Red-clawed crab, measuring around 2 inches across its shell or carapace. Males have one large claw and one smaller one, while both claws are he same size on the female. The Fiddler crab relies primarily on dead matter or detritus, bacterial growth, and fungus for its diet. Fiddler crabs also prefer somewhat brackish water. They will be happiest in an aquarium having a sandy substrate where they can occasionally burrow. Fiddler crabs get along with most tropical fish though are a bit more aggressive towards them than are the Red-clawed crabs, and will often attack a dying fish, saving the aquarium owner the necessity of disposal.
The Coconut Crab - One of the more interesting of the tropical crabs, and the largest, is the Coconut crab. The Coconut crab is almost entirely a land dweller. It will enter the water, fresh or salt, on occasion, but if submerged in salt water for several hours it would eventually drown. The Coconut crab is an excellent climber, having no problem scaling palm trees. They are sometimes kept as pets in the tropics but one has to be a little careful with them. Since their claws are strong enough to crack open coconuts, they can obviously deliver quite a painful pinch to hands or fingers, plus they have a reputation for being slow to release their grip.
Of the hundreds of species of tropical crabs we've touched upon three, only two of which would be at home in an aquarium. There are many more to choose from suitable for both fresh saltwater aquariums. As is the case with tropical fish, many tropical crabs are brightly colored or have interesting and colorful patterns, and many are available for purchase. Besides their care and feeding, it's good to know which other creatures will make good tank companions and which will not. One should also find out if more than one of a given species can be kept in the same tank. Sometimes the answer is no.