Paractaea monodi - for sure?

[Gromit1710]

I was getting ready to do a WC today and saw my emerald crab, merrily munching away on some algae. I plunked him in the tank about 2 weeks ago when my tank began to show serious signs of micro green infestation of a couple strains that started on some frag plugs. The little guy has been doing a great job of cutting it back.

 

I then walked around to the side of the tank to lift up the hood and something caught my eye.

 

Another crab that I've never seen in my tank before. WTF??

 

I researched around the web and came up with Paractaea monodi. It's already as large as my emerald, but is black with small white spots on it. The legs and claws fold up tightly against it's body to form a broad and flat oval shape when it's tucked together. The picture attached is not a picture I took of the crab, but a very close resemblance to the one I found today.

 

1) What is it?

2) Do I need to figure out how to get this out of my tank?

3) How about this weather we're having, eh?

[carbon-mantis]

Your ID looks like it's correct from the pictures. Can't find any information on the little fellow in English, but here's a foreign site that I ran through a cheap translator-

 

Click

[Builder Anthony]

Wwll if hes been in there a while and hasnt didi any damage i would just leave him in.

[Gromit1710]

It's strange that there's no descriptions in English. Just my luck... I get a bad crab exotic enough not to have a regular forum hate page....

 

 

As long as I don't see stuff getting munched, I'll leave him in there. He's kinda cool looking. But not too cool looking that if something starts getting eaten, to yank and feed to the tom cats in the 'hood.

[Gromit1710]

I saw him roaming around an hour after the water change.

 

Here's a pic of the actual crab I'm trying to ID.

 

another pic

[Builder Anthony]

Well you would have damage to corals by now if those were on his menu.I speak from experience.

[jedidad]

cool crab. hope you don't run into any problems with it.

[danthenewreefman]

yea you would 1000% know if it was bad for coral by now...

[GokesReef]

yea you would 1000% know if it was bad for coral by now...

 

When you say "by now" you imply that you know how long the crab has been in the tank.. which I don't think we know.

 

I agree with the no harm no foul, though.

[ajmckay]

IMO you should deal with it now... It's definitely not a reef safe crab. Crabs are opportunistic in many cases, so the "no harm, no foul" theory doesn't really apply long-term IME. It's probably just a matter of time before he picks something off whether it be a snail, a fish, or a coral. Do you know what he's been eating and what he's eating now? Once that is gone he'll likely switch to something else.

 

Do you have a sump ? You could stick it in there for some interesting stuff. You could give it to someone, or you could mash it up for fish food... I'm sure a local mantis shrimp owner (or puffer, trigger, etc...) would happily take it off your hands.

[Builder Anthony]

Ya t might eat a snail or there but corals are the main concern.It would have went after them by now.I had a crab similar to that that would eat flake food.I had it in with about 5 fish in a 75 gallon.Even if it did decide to go after something else i think having a little bit of a predator in a tank just makes it that more intrsting.Most fish have good sleeping spots.

[lakshwadeep]

That seems to be a very common xanthid crab, all of which should not be considered reef safe. Do a search for other xanthid hitchhikers, and you'll see nearly identical individuals.

http://www.chucksaddiction.com/hitchcrabs.html

[Shsnnon]

That seems to be a very common xanthid crab, all of which should not be considered reef safe. Do a search for other xanthid hitchhikers, and you'll see nearly identical individuals.

http://www.chucksaddiction.com/hitchcrabs.html

The crabs at the bottom of that page seem very cool. Now I want one. I think you're right though the pic looks like the xanthid. I guess that letting it live might turn the tank into an expensive Wild Kingdom.

[lakshwadeep]

Trapeziids (commonly called acropora crabs) are sometimes found as hitchhikers in SPS colonies.

[Gromit1710]

Well I can say with certainty that the crab was on the LR I purchased for the set up of the tank. I know that guy wasn't in my 8 gallon.

 

Up until now, I've not noticed any damage to corals, but Snails and the like have been killed. I haven't worried about it too much because it makes bigger shell homes for the hermits and snails are cheap.

 

I have no idea how in the hell I would get him out though without tearing my 'scape apart.

[GokesReef]

Search for bottle trap, pretty much the most common method.. invert the top of a sode bottle and put some food in there. Put it near his home.

[Gromit1710]

Search for bottle trap, pretty much the most common method.. invert the top of a sode bottle and put some food in there. Put it near his home.

Nice! Thanks for the tip!

[TheWAND]

I had one of those. Thought it was harmless at first. Then corals started disappearing. By the time I had caught it it was pretty large, about the size of two big turbos. Anyways, I caught it by putting a cocktail shrimp inside of a tall water glass and propping it up on a ledge after lights out. The crab was in the trap in under 5 minutes and i flushed it.