Freshwater hermit crabs are one of the rarest species of living things found on earth. Before starting a discussion on freshwater crabs, it is important to mention that these crabs are found in only a single lake in the entire world, and they are the rarest of the rare exotic animals.

There are several species of marine hermit crabs, and all but one are alkaline water inhabitants. Alkaline water crabs are native to different ocean regions around the world and retain this birth even during captivity. That means the salinity and color of your captive waters should be like that in your native waters. However, although many marine species of these crabs have adapted to a captive environment in the company of humans, it is impossible to keep freshwater crabs as pets. Being one of the rarest species, any type of human intrusion into its habitat is prohibited by international laws drawn up by the guardians of wildlife conservation.

The only freshwater reservoir where these rarest inhabitants of earth live is the Espirito Santo Roller Coaster Freshwater Pool, Vanuatu, in the southwestern tropical Pacific. This coastal lake is located near the town of Matevulu and is adjacent to an abandoned airstrip. The species of hermit crab that inhabits this coastal lake is the Clibanarius fonticola of the genus Clibanarius. Zoologists McLaughlin and Murray first reported this unique habitat of freshwater hermit crabs in 1990. Freshwater crabs are highly unique, preferring only the abandoned snail shells of the Clithon crown snail species. Clithon’s crown shells are found in its natural lake. The natural lake of Espirito Santo is fed with fresh water from nearby springs.

The reason for the unique habitat of freshwater hermit crabs can be traced back to the unique confluence of conditions of their magical lake habitat. Being always fed by streams, this freshwater lake has a flowing water condition that is so essential for marine crabs to reproduce. Also, since the lake is located in a coastal region, there must be underlying elements of alkalinity in the lake water that make this habitat so favorable for crabs. This confluence of running water and underlying alkalinity makes the pool the only ideal place for the survival of the species Clibanarius fonticola. The lake’s remote and private location is also one of the main reasons these crabs have chosen the lake as their only freshwater home.

Some of the other members of the genus Clibanarius such as Clibanarius erythropus, Clibanarius signatus, Clibanarius tricolor, Clibanarius snelliusi, and Clibanarius englaucus can live in marine aquariums if their native conditions are properly provided in their captivity. The genus Clibanarius, of the Diogenidae family, also has a very special identifying character. Unlike all other crabs, these crabs have an enlarged and decorated left claw, which is why they are also known as left-handed hermit crabs.

Although other marine hermit crabs don’t need fresh water, surprisingly, land crabs only drink fresh water to survive. In this sense, it is perhaps not irrelevant to baptize these land crabs as freshwater hermit crabs. These land crabs drink fresh water for their nutritional needs, but prefer to bathe in a container of alkaline water.