Red Clawed Crab

[blaqk]

hey, ive got a freshwater tank, but also a smaller tank which i want to keep a couple of red clawed crabs in. they are advertised as freshwater, but futher research says that they live 2 painful months in a freshwater because they're actually brackish. is this true? if so, is a brackish tank as simple as tropical just with a bit of salt? the layout of the tank was to be sea edge, a sand bank (so they can rest out of water) which slopes down into water. ill build little hiding places etc there for them aswell.
so to sum up:
has anyone kept them?
if so how long do they last in brackish water?

cheers

 

[iliveinazoo]

hey, ive got a freshwater tank, but also a smaller tank which i want to keep a couple of red clawed crabs in. they are advertised as freshwater, but futher research says that they live 2 painful months in a freshwater because they're actually brackish. is this true? if so, is a brackish tank as simple as tropical just with a bit of salt? the layout of the tank was to be sea edge, a sand bank (so they can rest out of water) which slopes down into water. ill build little hiding places etc there for them aswell.
so to sum up:
has anyone kept them?
if so how long do they last in brackish water?

cheers

Never kept them so i don't know how long they'll live but they are said to inhabit mangroves so i would reckon that a brackish aquarium with a salinity of between 1.005-1.015 would suffice. leave plenty of land for them to walk about on.

a brackish aquarium is just a tropical aquarium with salt - be sure to use marine salt though.

When you get above 1.005 it's almost impossible to grow plants.

 

[nmonks]

Perisesarma bidens is the common red-claw crab, and yes, it's a brackish water beast. That said, it's amphibious rather than aquatic, so ideally needs a vivarium similar to something you'd use for frogs. Add a shallow (inch or so) depth of brackish water, and that's it. If you didn't filter the water, at least replace once or twice a week. They do require heat and significant humidity though.

Cheers, Neale

 

[blaqk]

ok thanks for that, i was aware of them needing alot of land, thats why i was aiming for more of a 'sea side' look than a fish tank with a bit of bogwood or rocks sticking out above water level. so i just need to add marine salt to tap water and thats brackish then? doesnt seem to hard thanks

 

[nmonks]

Pretty much. 6-9 grammes per litre will be ample. Brackish is really very easy! Red-claws are notorious escape artists though, so that's likely your main problem -- keeping them in!

Cheers, Neale

so i just need to add marine salt to tap water and thats brackish then? doesnt seem to hard thanks

 

[blaqk]

yeah ive heard about that aswell! dont worry, the tank there in i had trouble getting into! my 4 foot tank is not very good for keeping things in though, my frog has got out a good few times! luckily we have always been there to put him back in again!
one last thing, would i have to cycle the system first? the tank has been used for years so is well matured.
thanks again, ill post photos up when i sort everything out!

 

[iliveinazoo]

yeah ive heard about that aswell! dont worry, the tank there in i had trouble getting into! my 4 foot tank is not very good for keeping things in though, my frog has got out a good few times! luckily we have always been there to put him back in again!
one last thing, would i have to cycle the system first? the tank has been used for years so is well matured.
thanks again, ill post photos up when i sort everything out!

If your tank has been constantly running with an ammonia source then you should be able to pop them straight into your fresh tank (since you say that you are buying them from a tank with fresh water) and up the salinity by 1.002 per week until the desired level however if your tank is empty or you don't have any fish in there at the moment then your bacteria will have died so you will have to re-cycle.

 

[Eclecticoldsod]

My experience with red claw crabs is that they do require 50/50 land and brackish water to be happy and thrive, but I have always given mine a much greater depth of water than is often recommended. There are two reasons for this:
1. Given 6 inches of water [with some plants and interesting décor to explore] they will spend a lot of their time in the water.
2. They are dirty little beggers, so a small internal filter will help to keep the water clean [in addition to water changes] and they need warm water and warm, humid air in the tank, so a small submersible heater is essential. These two items are almost impossible to run in very shallow water.
What I do is to glue a shelf of clear plastic [or glass] halfway across and halfway up the tank, with a cork bark edge to hold back about 2 – 3 inches of sloping fine sand. The water laps the lower level, with java moss and bog wood acting as a ramp. These crabs are great climbers, so access to and from the water is no problem.
Depending on the size of the tank, with this set-up you can keep a few brackish water fish along with your crabs.

 

[iliveinazoo]

I don't know what red claws are like but my fiddler crabs barely moulted until they were put in a dedicated tank of their own and now they moult very regularly

 

[nmonks]

I think you've hit the nail on the head. While some of us might argue over the precise details, like salinity or depth of water, the key thing is that these are amphibious animals that can't be kept in standard fish tanks. Once you understand that, things become a lot simpler.

Cheers, Neale

I don't know what red claws are like but my fiddler crabs barely moulted until they were put in a dedicated tank of their own and now they moult very regularly