suspicious of my crabs - over-reacting?

[elixir]

hi
i'm completely new to the hobby and one of my first purchased inverts (introduced 2 months ago) was a camel shrimp. its completey disappeared. is it possible the crabs ate it?<br />

besides a dozen hermit crabs, i've three flat crabs: two were LR stowaways, and one i caught at sea (Persian Gulf coast). i've no idea as to their species or safety for their fellow tankmates (90g FOWLR).

this is the largest of the three @ a full 1". any idea what it is?<br />
<img src="http://www.reefcentral.com/forums/picture.php?albumid=4771&amp;pictureid=33077" border="0" alt="" /><br />
<br />
this one is a tad smaller. is it the same family as the above? i witnessed it destroy a smaller black crab i had also picked up in the wild. so i'm suspicious it or one of the other two may have also been behind the disappearance of said camel shrimp. is my suspicion justified?<br />
<img src="http://www.reefcentral.com/forums/picture.php?albumid=4771&amp;pictureid=33078" border="0" alt="" /><br />
<br />
the 3rd crab, not pictured, is 3/4 inch and very hairy.

any help with IDing or advice would be greatly appreciated. i guess i'm more concerned for the fishes i intend to introduce than anything else.
.

[jdegrasse]

It's always hard to say for sure.

From the pics, they look like Xanthids. The hairy one may be a gorilla crab. Shrimp and other motile creatures are usually too fast for Xanthid crabs, if they are healthy.

I suspect that what happened is that the shrimp was sick or otherwise weakened and so could not react fast enough (or at all). Xanthids are ultimately opportunistic.

Maybe the shrimp molted and is hiding?

Reefers don't like Xanthids (black claws) because they tend to eat what ever doesn't run away from them. They should be fine in your FOWLR.

[elixir]

thanks for the info. thats reassuring.


Maybe the shrimp molted and is hiding?.

hmm. wouldnt suprise me as i've a load of hiding places in the LR. i didnt see a blenny for a month till yesterday when i took the rocks out for some rearranging. i guess i was somewhat freaked out by the violence of seeing one crab rip appart another.

here's the 3rd hairy crab, btw.
http://www.reefcentral.com/forums/picture.php?albumid=4771&pictureid=33156

is this what is called a gorilla crab, or just a hairy version of the xanthid?

[BEASTIEPENDENT]

Hi elixir, the latter one could be a Pilumnid crab (don't know the english vernacular names and they change from country to country). Pilumnus spp. mostly are predators, some even feed on some corals.

The two above do indeed look like Xanthids, and they seem to have sharp pincer tips and not spoon shaped – that means at least they are no primarily algae eaters. It could be that they are quite unscrupulous predators… If You have a sump and feed them from time to time they go quite well there although it might be to small and have no or not enough hiding places for more than one crab.

[jdegrasse]

+1 on pilumnids