Hitchhiker Crab ID Please

[gilly23]

Hi, this is my first thread here and i need some help. I had my 150 Gallon tank for two months now and all of the coral and fishes are heathly and nothing has gone missing but i found out that a crab is in my tank.

Here is the desciption, it has black claws (kinda big) and hairy feet. Its black and its eats stuff off my rocks. I hope that it doesnt go and eat my 5 shrimps and fishes, here is a picture and can you please tell me if its safe or dangerous. If dangerous how do i catch it? Thanks

[Reefland]

Hi gilly23,

It is really hard to tell but by rule, craps are opportunistic omnivores. Given the opportunity, they can go after the desireable's in your tank. With that said, it is often times hard to catch these little guys, but if you can I would and put it into a refugium or other safe place.

[gilly23]

Hi gilly23,


It is really hard to tell but by rule, craps are opportunistic omnivores. Given the opportunity, they can go after the desireable's in your tank. With that said, it is often times hard to catch these little guys, but if you can I would and put it into a refugium or other safe place.

Can you tell me how can i get this little guy? Here is another pic that took off someone but i think its the exact kind in my tank but its getting bigger each time i see it. Can you please ID it and the name of it, thanks

[Ninong]

Hi gilly23,




I suggest removing that crab from your aquarium.

Good luck!

[FireEater]

You can try to squash him with a large wooden dow rod. I have done that before.

You can set a small glass in your tank next to his home. Put a piece of food in it and he might go in it to eat the food. If you have the glass at an angle he will not be able to crawl out.

I put this in my tank to show you how to do it. Put it at a slight angle with the lip by his home.


I just found this bleepity bleep in my Pocillopora Coral a few minutes ago. I have no idea where he came from but I can tell you where he is headed.

He seemed to munching on the coral like it had algae on it. Not sure if he was trying to eat the polyps or not.

Now to try and ambush him.

[TimH07]

wow, how about that coincedence, try the cup idea!

[Ninong]

I just found this bleepity bleep in my Pocillopora Coral a few minutes ago. I have no idea where he came from but I can tell you where he is headed.

He seemed to munching on the coral like it had algae on it. Not sure if he was trying to eat the polyps or not.

Now to try and ambush him.

I can't make out very well what your crab looks like but check out these images of Trapezia cymodoce. Does your crab look like that?

T. cymodoce is a commensal symbiont of corals in the family Pocilloporidae. You might want to let it be and see how things work out? You can read about it here.

[FireEater]

Yea, I figured that out. He is safe now.

[gilly23]

Can you tell me how can i get this little guy? Here is another pic that took off someone but i think its the exact kind in my tank but its getting bigger each time i see it. Can you please ID it and the name of it, thanks

So i guess i have to take it out. This crab has gotten rather big now and i have set a trap already but no luck so far, usually how many days can i catch this guy?

[returnofsid]

In your last pic, I see black tips on the claws. That's usually an indication that this is a nasty crab you want removed!! As has been mentioned, most crabs are NOT good. There's a few that are fine but usually don't end up in your tank as hitch hikers. One common rule of thumb is that if the claws have black tips, they're BAD.

As for catching it, one option is to keep an eye on what piece of live rock it's hiding in and remove that piece. With a little shaking and swishing around in salt water, it may come out. Other suggestions would include traps with bait in them. You can cut the top portion of a 1 liter bottle off, invert the top and push it back into the body of the bottle....this creates a funnel that the crab can get into but not out of as easily. Then bait it and hope for the best.