Crab Id Please

[aquariagirl1976]

Hi! I bought a crab at my LFS, and just was wondering if he had a specific name. I took a pic, tho a pretty bad one I will admit. He is basically brown on the top of his body, and red on his claws and underbelly.

Thanks!

 

[three-fingers]

It will be a red claw crab Sesarma bidens (although it could be another Sesarma species, a clear pic is needed to be 100% sure, it is unlikely) . They need somewhere to climb out onto and brackish water, you wont have success with him over he long run in freshwater, although I've heard of someone keeping one alive for around a year in hard alkaline water

 

[aquariagirl1976]

Great! Thanks very much. I do add some salt to my tank but not enough to be considered brackish.

 

[three-fingers]

What type of salt do you add to the tank?
And what else lives in it?

 

[aquariagirl1976]

It will be a red claw crab Sesarma bidens (although it could be another Sesarma species, a clear pic is needed to be 100% sure, it is unlikely) . They need somewhere to climb out onto and brackish water, you wont have success with him over he long run in freshwater, although I've heard of someone keeping one alive for around a year in hard alkaline water

I have done a little research on him, here is what I got from http/www.aquariumfish.net.

"The Red Claw Crabs are very attractive with black or very dark maroon bodies and red claws.

These Red Claw Crabs and the Gold Fiddler Crabs are truly aquatic and do not need to get out of the water. They can live indefinitely on the bottom of your aquarium completely under water. Both of these Crabs do well in fresh water."

I suppose if he did want to get out of the water, he could crawl up the air lines tho.

 

[aquariagirl1976]

What type of salt do you add to the tank?
And what else lives in it?

I use aquarium salt, and my list of tanks and inhabitants are in my sig. And yes, I know I will have to move him once my bichir gets bigger.

 

[three-fingers]

Unfortunately, aquariumfish.net is wrong .
They are for one, not completely aquatic, and secondaly, they are not 100% freshwater crabs.
In the wild they mainly live in brackish water, though periodically live in freshwater. They go to the sea to spawn.

They do need to come out of the water, and your crab will eventually try climbing out unless it's ill and weak or something.

Unless when you say 'aquarium salt' you mean the stuff for marine aquariums, then adding it is pointless - as it is just sodium chloride.

The crabs need the salt because it provides all the right minerals for their shells and raises the pH.
This is why they can do OK in freshwater with a high dissolved mineral content (hard with a high pH) for quite a while sometimes.

'Aquarium salt' does neither of these two things, aquarium salt is really only useful for salt baths when treating fish - adding it to the tank does lower the toxicity of nitrate too, but this should never be needed .

If you want to keep the crab in that tank, you will have to modify it.
Boboboy from this forum has his tank so the cabs have something to climb out onto, and they have a little brackish water bath to retreat to (this water needs to be changed everyday).

EDIT: Left a sentence unfinished .

 

[GoldLenny]

It will be a red claw crab Sesarma bidens (although it could be another Sesarma species, a clear pic is needed to be 100% sure, it is unlikely) . They need somewhere to climb out onto and brackish water, you wont have success with him over he long run in freshwater, although I've heard of someone keeping one alive for around a year in hard alkaline water

I have done a little research on him, here is what I got from http/www.aquariumfish.net.

"The Red Claw Crabs are very attractive with black or very dark maroon bodies and red claws.

These Red Claw Crabs and the Gold Fiddler Crabs are truly aquatic and do not need to get out of the water. They can live indefinitely on the bottom of your aquarium completely under water. Both of these Crabs do well in fresh water."

I suppose if he did want to get out of the water, he could crawl up the air lines tho.

Remember to always do your research separate and independent from almost any place that sells fish/critters. They try to spin things to make sales... often without regard to the long term health of the fish/critter. Same goes for getting advice from most pet stores or LFS employees. There are exceptions but I'd say 90% give bad advice. Aquariumfish.net is notorious for giving bad advice. It's an OK place to start but everything should be vetted by independent resources.

'Aquarium salt' does neither of these two things, aquarium salt is really only useful for salt baths when treating fish - adding it to the tank does lower the toxicity of nitrate too, but this should never be needed

Just to point out a typo... salt is useful for lowering the toxicity of nitrites... not nitrates. One teaspoon will treat 400G and protect again nitrite poisoning (brown blood disorder) for nitrites up to 2.5ppm. Just a pinch is needed in a 10G tank.

 

[raptorrex]

It will be a red claw crab Sesarma bidens (although it could be another Sesarma species, a clear pic is needed to be 100% sure, it is unlikely) . They need somewhere to climb out onto and brackish water, you wont have success with him over he long run in freshwater, although I've heard of someone keeping one alive for around a year in hard alkaline water

I have done a little research on him, here is what I got from http/www.aquariumfish.net.

"The Red Claw Crabs are very attractive with black or very dark maroon bodies and red claws.

These Red Claw Crabs and the Gold Fiddler Crabs are truly aquatic and do not need to get out of the water. They can live indefinitely on the bottom of your aquarium completely under water. Both of these Crabs do well in fresh water."

I suppose if he did want to get out of the water, he could crawl up the air lines tho.

ohh hold on there people!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
this is to be honest is BULL####!!!!!!!!! both crabs live on land, not in the water. given a natural environment, both these crabs are estuary dwellers. foraging at the waters edge at low tide, sleeping buried in the sand as the tide comes in. Truly aquatic crabs, seem to be sea dwellers. though I would bow to better knowledge. please believe that i am not having a go at the posters in this thread, its the dim wit who put the site together who is to blame. god man, as a hobby we are responsible for the loss of a vast number of fish per year, why do people make it worse by posting clearly false info on their sites?

 

[three-fingers]

Just to point out a typo... salt is useful for lowering the toxicity of nitrites... not nitrates. One teaspoon will treat 400G and protect again nitrite poisoning (brown blood disorder) for nitrites up to 2.5ppm. Just a pinch is needed in a 10G tank.

Not a typo, aquarium salt was apparently used to be used in the days of old to lower the toxicity of nitrates in tanks with 'old water' (very few or no water changes).

It's more useful nowadays for lowering the toxicity of nitrites, but only really in emergencies or when shipping fish long distances, so there's no need to add it to a perfectly functioning aquarium. No harms done by adding though in the small recommended doses, just a waste of money IMO really .

 

[Invader Xan]

Apparently, there's a different (but related) species of crab that will do well in freshwater (or so I was told). Geosesarma sp. is sold in Germany. I don't know for certain, but I've been investigating these little guys. They have a few colour morphs - including orange, 'tomato' and 'vampir' (purple). I'd imagine they'd still need to climb out of the water from time to time, though TBH I'm don't know for sure.

While on the subject, I was wondering if a crab might do well in water with a low salinity (say, sg 0.05) but a high GH/KH level. Anyone?

 

[dizzied]

There's actually quite a number of geosesarma species found in the hobby. They are most common in Germany than anywhere else it seems, like most freshwater inverts. Based on the genus name alone, you could assume they're terrestrial/semi-aquatic.

The thing about freshwater and brackish crabs found in the hobby are that they're not really aquatic creatures that need land, but terrestrial creatures that need water. There used to be a few dedicated forums to keeping these crabs, but they've all seem to died off. I've had to go from seeing amazing setups that are only about 20% filled with water to seeing red claws climbing up airlines to keep themselves alive.

I'm sure crabs would prefer a high GH/KH as opposed to a low one.

 

[Invader Xan]

I wonder if there even are any fully aquatic freshwater/brackish crabs...

 

[three-fingers]

I think there is, I have heard of a geosesarma species that lives at the deepest part of freshwater lakes and moves to shallower areas during the night, but I'm not 100% sure about this because I cant find the document .

I've never heard of any fully aquatic brackish/freshwater crabs in the hobby though.

 

[raptorrex]

i have heard of redcrab breeding at 1gram per litre salt content. though this would seem low, it also seems to keep these crabs healthy, when they live in a freshwater tank and only have a brackish bath, not ideal i know.