Another crab ID?

[Wilky]

I spotted a new crab a couple of weeks ago, it was tiny and would have been impossible to catch. I found it again the other day and its grown a lot. I managed to snap a couple of pics so i'm hoping someone can help me to id it?

First thoughts are some type of mithrax crab? It's body is smooth and patterned black and white. Claws are slim and long and legs are black and white but covered in brown hair.




Long Claws:




Hairy Legs:

[The Heathen]

if its grown that quick in a couple of weeks it looks like it could be a problem in a couple of months time Ian..


sump it


Better safe than sorry .

[Wilky]

i will if i can catch it,

Ta

[Linda]

I had a bit of a scout round earlier and the only black and white ones I could find were Xanthid crabs, and considered to be not reef safe

[Wilky]

Thanks Linda, could well be... i intend to remove anyway but he's in hiding for now and i've no idea how i'll get him out yet.

[Wilky]

Well this guy is still about, but is very reclusive so i've still no idea how to catch him.

A recent moult was more or less intact so managed to finally get a decent pic of what he looks like, the nice black and white pattern has gone, and defo has all the indicators of a bad guy - blue eyes, hairy legs etc.. but touch wood, he's still only picking at rock and algae and i've suffered no losses.

[tonyesox]

It looks simular to this one http://t0.gstatic.com/images?q=tbn:n4tc ... thrax7.jpg If so this is a type of black mithrax crab which is ok. I am not sure about the claw size thou so see what others say bud.

[Leyton]

Scoped pincers usually mean algae grazers but its still a crab, if it has the chance of an easy, meaty meal it will take it

[Wilky]

After just ID'ing this crab on Trev's tank thread it looks as though this crab is playing the innocent algae grazer during the day when i can see him...

But i think he may be responsible for this:



Definately looks to me like something has been having a go at it rather than recession, judging by the polyps immediately below being fine and the flesh still relatively healthy around the wound?

[TrevNW]

Sorry I didn't get a pic of the effect my crab had on the Seriatopora guttatus, but the damage mine did was very different. Basically the small brown one lived around the base of the colony and moved out to only about half way along the branches. It "hugged" them with it's legs and appeared to be constantly "grazing" at the surface. It was there for months. Eventually (the coral had had enough?) and the stripping began at the base and moved rapidly out to the branch tips. Mine never caused damage like your picture shows, but then it was probably a different beast.

Hmmmm

[Wilky]

Thanks Trev, when this guy was tiny he acted in a very similar manner (and looked just like a commensal crab starting out very light coloured - hence leaving him in). Maybe there is another culprit in there then but the only recent addition is a splendid dottyback which shouldn't be remotely interested in the corals

[set59]

I wouldn't trust it Ian. I have one in mine who appears to be grazing and bit by bit I have lost two small colonies of clove polyps and yellow polyps and these were on the rocks he likes to graze on. My GSP has gone down by half and I found him grazing there so he will be removed asap now. Its a shame they do this as they are great to watch. But I will have to be careful as he has a very loud click so don't want him hanging off my fingers I know I am talking about softies in mine but with Trevs experience too! Mines only in my Betta 680 so hoping it will be easyish. But yours must be a nightmare to get at

[Wilky]

Hi Sue, i don't trust him at all... I have a plan - waiting for him to go into one of his daytime places - a rock with a shallow tube like cave, right at the front with two entrances, the plan is to net one side and poke a stick through the other

[TrevNW]

Hi Sue, i don't trust him at all... I have a plan - waiting for him to go into one of his daytime places - a rock with a shallow tube like cave, right at the front with two entrances, the plan is to net one side and poke a stick through the other

Or you could milliput up both entrances when he's in I know it sounds cruel but when you're lossing £££ of corals and catching the culprit is neigh on impossible.......