ID Spider Crab?

[Raphael Dalmeida]

Hi,

I've got this Spider Crab with a piece of rock.

I'd like to know if it's reef safe or not, and if it will try to predate on any of my fish while they sleep? Or bother corals.

I've read there are many different types of spider crabs, and some could be reef safe while others not so much. Can't really pinpoint with this one.

Some photos below (taken from top or front).

 

[blaxsun]

Possibly a decorator crab? (just a guess)

 

[Tired]

Nice find, I love these!

This little guy is a decorator crab. They don't get too large, and their small claws mean anything that's mobile and not badly injured should be fine. Shouldn't be a threat to fish, shrimp, or the like. May eat snails if it's starving, but so will a lot of things. They're mostly scavengers and algae-eaters, and will eat the occasional amphipod if they get a chance.

They do snip and wear soft corals, but the corals often grow on their backs just fine after being snipped. If you have tiny frags of expensive zoas, either put them on magnet frag racks (he can't climb glass) or put this guy in a sump or 'fuge. Anything else should be fine- and that includes zoas, if the colony is reasonably sized. Worst he'll do is rudely frag a chunk off and quite possibly wind up propagating it.

If you don't want it, offer it up to your LFS and/or on here. Someone will probably take it.

 

[Raphael Dalmeida]

Possibly a decorator crab? (just a guess)

It seems that there could be many types of decorator / spider crabs ? Some better and some worst.

Just wondering if anyone can give a bit more insight into it.

Thanks though.

 

[Raphael Dalmeida]

Nice find, I love these!

This little guy is a decorator crab. They don't get too large, and their small claws mean anything that's mobile and not badly injured should be fine. Shouldn't be a threat to fish, shrimp, or the like. May eat snails if it's starving, but so will a lot of things. They're mostly scavengers and algae-eaters, and will eat the occasional amphipod if they get a chance.

They do snip and wear soft corals, but the corals often grow on their backs just fine after being snipped. If you have tiny frags of expensive zoas, either put them on magnet frag racks (he can't climb glass) or put this guy in a sump or 'fuge. Anything else should be fine- and that includes zoas, if the colony is reasonably sized. Worst he'll do is rudely frag a chunk off and quite possibly wind up propagating it.

If you don't want it, offer it up to your LFS and/or on here. Someone will probably take it.

Nice thanks for the info.

I quite like him it seem very quirky. I do have quite a few zoanthids in the tank and some macro algae.

I might try to free him there and would find it cool if he starts decorating himself as long as he doesn't bother fish and don't really kill any coral. Occasional zoa wearing should be fine

 

[Tired]

If you have zoas and macros that can stand a little trimming, this is an excellent little guy to have in your tank. Nice to play a game of "where is he now", and fun to see how he changes his costume. Interesting how they choose their decor. My current one is pretty tiny- can't wait until he gets big enough to gather more stuff.

Feed him a couple times a week, and he should do well. They rapidly learn to take food from tweezers or tongs, which is fun, and should be reasonably able to find scraps your fish miss.

You might have more. Keep an eye out for lumps.