# Miscellaneous Herp Interests > Invertebrates >  Freshwater Crab ID

## invadertoast

Hey Guys - I've posted this on a couple fish/invert. forums but I figured I'd try it here too seeing as there are some fish people here!

My mom and I went out earlier today to pick up some neon tetras for my 29gal community tank. We saw these neat little purple crabs in with a tank full of tetras and they were just too cool! The people getting fish before us asked about them and the woman working (who seemed to really know her stuff, after listening to her reccommend things for other customers) said they have been getting them for the past 8 months and that they eat algae. She has had great luck with them in the store and had no customer complaints about them bothering fish (their claws are TINY) With a price tag of $2.99 we decided to get a couple for my tank. I have 3 zebra danios, 3 cory cats, and 4 female bettas living peacefully in my tank. Today I added the 6 neons and these two crabs.

They were labeled "Thai Blue Devil Crab" but I can't find a SINGLE bit of information about them!! Can somebody please help? I was fully expecting to find all kinds of information on them but I can't find anything... I just want to be sure my fish and my crabs will be happy (I have an empty 5 gallon they can be moved to if problems arise) They're so colorful I can't help but wonder if they are really brackish water creatures?? I feel kind of silly as I'm not usually one to impulse buy, but this store has a fantastic reputation so I felt comfortable believing what I was told.






Thanks in advance!

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## jknudson

Looks like a female Uca sp.  We've had them at work labeled as "Blue Fiddlers".  Hope this helps your search for info.

 :Good Job:

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## Patrick Long

Fiddler crabs have one large claw, and one small claw, like someone holding a violin (hence fiddlers crab). I sent the pictures to a friend of mine, he said he would get back to me!

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## jknudson

> Fiddler crabs have one large claw, and one small claw, like someone holding a violin (hence fiddlers crab). I sent the pictures to a friend of mine, he said he would get back to me!


Pat, only the males have one large claw and one small claw. Females have dual small claws. :Wink:

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## Patrick Long

see i knew it, the guy at the fish store here in town was wrong! He was trying to sell a crab with two little claws, that i SWORE was a fiddler crab, but he said it was some crazy species i have never heard of!

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## python.princess

i dunno but they're pretty groovy lookin!  :Very Happy:

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## invadertoast

Hmmm... the store I got them from had fiddlers (males and females) in another tank and they didn't quite look like these guys. ALL the crabs in the tank these came out of had matching tiny claws. The ends are rounded over and not sharp at all. I've been searching for hours and can't find anything like them, especially with the rediculous orange eye stalks, lol.

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## Patrick Long

look at the eyes of the velvet swimmer, you think as an adult it could look like that?

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## invadertoast

> look at the eyes of the velvet swimmer, you think as an adult it could look like that?


Hmmm... nope, still no match, they have a groove along the front edge of their body that they eye stalks fold down into (I'll try to get a pic tomorrow if I catch one of them doing that)  The velvet swimmers don't seem to have that groove and instead have some spikey looking things. This is gonna drive me nuts! lol

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## jknudson

> Hmmm... nope, still no match, they have a groove along the front edge of their body that they eye stalks fold down into (I'll try to get a pic tomorrow if I catch one of them doing that)  The velvet swimmers don't seem to have that groove and instead have some spikey looking things. This is gonna drive me nuts! lol


There are literally hundreds of species of crabs....much of which are only subtly different, I don't know if you'll find the exact species.  I'm pretty positive it IS a fiddler species.  I sell those at the shop I work in...but keep searching if you must.  Care is simply as a standard fiddler crab.

http://www.fiddlercrab.info/uca_species.html 

There are 97 or so species of fiddlers....take a look at some, they have the defining characteristics you're describing.

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## invadertoast

Thank you!! Looks like I've got alot of reading ahead of me, lol

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## Debbienflorida

FYI - Most freshwater crabs need a dry space to get out of the water occasionally and an escape proof lid on the tank.

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## invadertoast

We have a winner???
http://www.crusta10.de/templates/ind...bff60504ec9180

Unfortunately one of them didn't make it through the night, the other one looks fine, but will be getting her own brackish half-land tank later today.  My 29 gallon has an eclipse hood with no possible escape route, and a 3-D foam rock background that one has figured out to climb up to the surface. I'm gonna be taking the dead one back to the store with some info for their fish lady...

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## Schlyne

Good luck!  I think they are really neat looking crabs.

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