Hermit Crabs

[justinp]

I currently keep fiddler crabs in my brackish tank and have done so successfully for almost two years now...I also have some small blue hermit crabs in my Marine setup and was wondering if Hermit crabs can live in Brackish water? I have gotten different answers from so many people...Has anyone done this?

 

[nmonks]

There are indeed lots of hermit crabs that live in brackish water... the problem is that you cannot easily identify the species sold as marine invertebrates, and hence there's no way to tell if that species is one of the low-salinity tolerant species.

The terrestrial hermit crabs, on the other hand, usually do fine with brackish water. There are quite a few web sites on terrestrial hermit crabs, and these will help identify those species that dip into fresh water and those that use brackish water.

http/www.hermit-crabs.com/species.html

(The science on this page is a bit off -- I doubt Ecuadorian crabs have adapted to salty water; surely it's much more likely that only the Caribbean crab has adapted to freshwater, given that hermits evolved in the sea?)

Anyway, while paddling about around a brackish water lagoon in Florida last year, I was staggered to see just how many hermit crabs there were on the mud. Seems hermits are a very characteristic part of the fauna, and would definitely be a nice addition to a brackish tank.

Cheers,

Neale

 

[justinp]

There are indeed lots of hermit crabs that live in brackish water... the problem is that you cannot easily identify the species sold as marine invertebrates, and hence there's no way to tell if that species is one of the low-salinity tolerant species.

The terrestrial hermit crabs, on the other hand, usually do fine with brackish water. There are quite a few web sites on terrestrial hermit crabs, and these will help identify those species that dip into fresh water and those that use brackish water.

http/www.hermit-crabs.com/species.html

(The science on this page is a bit off -- I doubt Ecuadorian crabs have adapted to salty water; surely it's much more likely that only the Caribbean crab has adapted to freshwater, given that hermits evolved in the sea?)

Anyway, while paddling about around a brackish water lagoon in Florida last year, I was staggered to see just how many hermit crabs there were on the mud. Seems hermits are a very characteristic part of the fauna, and would definitely be a nice addition to a brackish tank.

Cheers,

Neale

How much dry land do these guys need?

 

[nmonks]

Quite a lot. Certainly a couple of square feet. A tank for mudskippers or fiddler crabs would be the sort of thing. What wouldn't work is a regular fish tank with a rock above the waterline. These crabs forage and burrow (which is essential) on land. The water is merely for bathing.

How much dry land do these guys need?

 

[CFC]

The small blue legged hermit crabs that are sold as clean up crew for marine reef tanks do fine in brackish water with a SG of 1.010 upwards, we have 17 in our brackish tank all of which have grown considerably since we got them and swapped shells at least once each.
When first purchased i acclimatised them over a few hours by dripping water through a length of airline from the brackish tank into a bucket of sea water that they came in until the SG near enough matched and the first few have now been crawling around the tank for nearly 3 months. We have found them to be invaluable for clearing up uneaten food left by messy eating fish like scats and picking out the odd prawn or whitepait that gets trapped within the rockwork, the tank is spotless now.

 

[nmonks]

Fantastic! Thanks for sharing this.

I've often wondered how many of the marine inverts (other than corals, obviously) were not actually collected on reefs but on rocky shores and suchlike near to the fish exporters' warehouses. Stuff like crabs and snails and suchlike. I know that the upside-down jellyfish (Cassiopeia andromeda) is a mangrove inhabitant, so should be fairly tolerant, and the horseshoe crabs definitely are euryhaline beasties.

Cheers,

Neale

The small blue legged hermit crabs that are sold as clean up crew for marine reef tanks do fine in brackish water with a SG of 1.010 upwards...