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Invert Warrior
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Discussion Starter · #1 ·
Several different auctions (yes I'll be careful with my wording) are offering 'Fully freshwater and not territorial mud crabs'

As I've never heard of these before, I'd like to know If anybody else has! Something does not seem right with that description. They sound a lot like Thai Micro Crabs.


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Invert Warrior
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Discussion Starter · #3 ·
Arent micro crabs fully aquatic? Wouldnt that rule them out of the "mud crab" group?
These mud crabs are labeled fully aquatic. Which is why I'm posting this.


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Invert Warrior
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Discussion Starter · #5 · (Edited)
Sorry. Here's an auction number.

160927095659

Strictly looking to discover the species of the crab and if it is really fully freshwater aquatic.

View attachment 58762

That's the sellers pic.


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MABJ I hate you! lol You could of included all the info they gave for the crabs! Searched ebay to see if I could find these crabs and they're Dwarf Mud Crabs (Rhithropanopeus harrisii). Could of saved me an hour of lookin at pics! lol The impression I've gotten were that they were fully aquatic but nothing flat out states it that I've read.
 

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Per the USGS Site:
Remarks: This crab is usually associated with some type of shelter or structure including, oyster reefs, living and decaying vegetation, and various kinds of marine debris in fresh to estuarine waters(Williams 1984). The Harris mud crab can tolerate a wide range of salinity which may explain its success in transport to other areas. Larval development also takes place under a broad range of environmental conditions (Costlow et al. 1966). The mud crab has established breeding populations in some Texas reservoirs and the life cycle can be completed in freshwater. Keith (2005) noted that ovigerous females, zoeae, and small juveniles have been collected in the Possum Kingdom and Tradinghouse Creek reservoirs.

http://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=197
 

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Never seen this crab before. If it can live and breed in freshwater I might have to get some. Maybe someone here has them and can shed more life on how they do in aquariums.
 

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Invert Warrior
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Discussion Starter · #10 ·
MABJ I hate you! lol You could of included all the info they gave for the crabs! Searched ebay to see if I could find these crabs and they're Dwarf Mud Crabs (Rhithropanopeus harrisii). Could of saved me an hour of lookin at pics! lol The impression I've gotten were that they were fully aquatic but nothing flat out states it that I've read.
Hope you remember I appreciate you!! :) lol thanks for looking. It really looked close.



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Invert Warrior
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Discussion Starter · #11 ·
Per the USGS Site:
Remarks: This crab is usually associated with some type of shelter or structure including, oyster reefs, living and decaying vegetation, and various kinds of marine debris in fresh to estuarine waters(Williams 1984). The Harris mud crab can tolerate a wide range of salinity which may explain its success in transport to other areas. Larval development also takes place under a broad range of environmental conditions (Costlow et al. 1966). The mud crab has established breeding populations in some Texas reservoirs and the life cycle can be completed in freshwater. Keith (2005) noted that ovigerous females, zoeae, and small juveniles have been collected in the Possum Kingdom and Tradinghouse Creek reservoirs.

http://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=197
Nice info!

I'm really curious if anybody has kept these...

I would bet they would be VERY popular if they could:

Breed in fresh water

Live healthily in fresh water

Stayed a small size (advertised that they are 1 1/2 inches)

Weren't aggressive.

The bit about the bacteria piqued my interest, however.


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Discussion Starter · #12 ·
Never seen this crab before. If it can live and breed in freshwater I might have to get some. Maybe someone here has them and can shed more life on how they do in aquariums.
Yeah! I'd trust it if Msjinkzd brought them in and had bred them.

I'd be very interested to know if anybody here has kept these.


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Invert Warrior
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Discussion Starter · #14 ·
Yea I might actually buy if there was any information and it wasn't so cold here now.
Agreed. I'm wary every vendor not on TPT. Seems like too much incentive to catch things, mislabel, sell for a lot to hobbyists.

If there are generations that have been raised in FW, I'd love to try.


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Doesn't matter if they are supposed to be fully aquatic or not, I bet the little buggers will still find a way to escape!! Until they find a way to make some sort of electrical fencing for crabs like they use for dogs not a chance I've every try them again!!! :D
 

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Discussion Starter · #16 ·
Doesn't matter if they are supposed to be fully aquatic or not, I bet the little buggers will still find a way to escape!! Until they find a way to make some sort of electrical fencing for crabs like they use for dogs not a chance I've every try them again!!! :D
What crabs did you try?

Most fully aquatic crabs will not try to escape.

Thai Micro Crabs love staying in the water.

Fiddlers aren't fully aquatic at all.


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Discussion Starter · #17 ·
Guys, this is from the seller, it lines up with that species page.

I think some of us should test this out. I asked where he gets his, if he is using tank raised crabs.


QUOTE:

"Hi Mark,

Dwarf mud crabs are found in coastal freshwaters, along with bays and estuaries with low salinity (under 6 ppt). They can/will breed in freshwater, however, it is recommended that the larvae be raised in brackish water (10-15 ppt) for about 3 months. The mother carrying the eggs can tolerate the higher salinity and can be removed after the larva have left her abdomen. The larval crabs will need access to live foods, like rotifers and newly hatched brine for proper growth and development. Also, you must keep the larvae in a bare tank with a sponge filter to stop the larvae from getting sucked into the filter system. Males differ from females by having a narrower abdomen, while in females the abdomen is slightly wider. You really need two to compare. The difference is not as obvious as with blue crabs or fiddlers.

Some articles have proven that this species has been reproduced/reared successfully in lab conditions. Also, they have been found in landlocked lakes in Texas, proving that they must be able to reproduce in pure freshwater to some extent. Adult size is about 1.5" but usually smaller. They are currently eating sinking pellets. Life span is at least 5 years (with young ones, I have kept this long). They are completely non aggressive, but will eat dead or dying tank mates. They tend to leave plants alone, but will consume beard algae on rocks and wood. They don't care for very low pH either (6.5- 8.5 best). thanks"



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I am sure I have a couple 20G's laying around, I can try breeding these in brackish/fresh if you're too afraid to commit yourself to the task. :p

I LOVE crabs, but hate how I can only keep a couple in a tank, if even that. Thai Micros are nearly impossible to breed, so fully freshwater aquatic crabs are always a sweet find.
 

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Invert Warrior
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Discussion Starter · #19 ·
I can try breeding these in brackish if you're too afraid to commit yourself to the task. :p

I am sure I have a couple 20G's laying around
Hehe! I'm not afraid. Time is the constrictor. I'm lucky I do all my schoolwork on my iPad, so I can be on here often.

More than the brackish water stuff, I'm sure people would be interested in a freshwater breeder. Could these adapt to it over time? Seems like they did in Texas. That's the breeding project I'd like to see lol.

I coaxed out of him how he gets his crabs.

QUOTE:

"Yes, I have raised them before(many scholarly articles online about raising them too). However, I collect them now because of other projects. Males will find out females after she molts. So breeding them depends on the female's molt cycle. You will see the pair venter to venter at night. The ones for sale are WC juveniles. The juveniles do better and live longer. Also, they can be sexed and breed at very small sizes, about 1/4 inch. Most individuals come from Vermilion Bay, S. Louisiana. Salinities are low there, and most individuals are collected in nearby canals. Thanks"


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Yeah I did some quick scanning of those said scholarly articles, they CAN adapt to breeding in freshwater but their larvae require a brackish environment for optimal growth.

In the wild the live mainly near estuaries where the water is more brackish than fresh. The ones that get landlocked are reported to have lower population densities due to unknown causes.

I think it's because they feed on artemia and other microscopic critters that live in the water, and there are few of those in fresh water systems in terms of density.

I'll do some more research, hopefully find a comprehensive guide to their lives so I can figure out what they need to breed optimally in freshwater, because apparently in brackish water they breed like mad!
 
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