An Intruder!

[tmreynolds]

Wonders never cease!

Came home to find a fairly large crab (relatively speaking) in my tank. I also found one of my small porcelain crabs dead, not sure if its related?

The intruder was about an inch wide on its shell with fairly substantial legs and fairly large pincers. The crab was fairly dark (was under a rock so hard to tell exact colour) and I think had some red spots or speckles (not 100%).

It was larger than my porcelains and I was very surprised to see it, it may have come with the original LR, but also may have come with my soft corals I bought recently on some small bits of rock. Can't believe I missed it!!

Anyone have any guesses about what it is, and whether its dangerous for my tankmates?

 

[steelhealr]

Photo. SH

 

[tmreynolds]

Photo. SH

Will try but its disappeared again, and it was in a position that I couldn't get a shot of...

Looked a bit like the 3rd pic down here Link

 

[tmreynolds]

Don't know how I got this as the lights were off and I couldn't focus properly, first time I've used manual mode on the camera...

Any ideas?

 

[sparklefuzz]

Don't know how I got this as the lights were off and I couldn't focus properly, first time I've used manual mode on the camera...

Any ideas?

Looks to me like a Black Fingered Mud Crab or "Xanthid Crab" Apparently not reef safe. Someone please confirm or deny this guess!

 

[ostrow]

Get it out of there! To the sump he goes.

 

[Mr Miagi]

Could your Porcelain Crab have moulted? How do you know its dead? I recently came across a Xanthid type species in my Nano. They are omnivores, and will take advantage of a food source, so you might want to remove it to a sump, or, alternatively, give it away, or it gets the hammer. Good food for nems, or other fish.

 

[tmreynolds]

The porcelain could have moulted, lord knows I've been scared 3 times recently by my shrimps "dying" only to find out they were moults..

I have only seen one porcelain knocking about since, although they are quite shy, I'll keep my eyes peeled.

I'll try to remove the intruder, but that will be easier said than done unfortunately. I don't really want to remove loads of LR unless I absolutely have to.

I watched him last night and he was picking at the LR, but he did have a look in his eye, I don't trust this fella...!

I'm still confused as to where he came from, its not your normal tiny hitchhiker.

Cheers guys,

 

[tmreynolds]

Ok, I can see a thread appearing shortly entitled "how to catch an intruder crab that sneaked passed security into your marine tank"

He's very shy and bolts for cover whenever there's movement.

I remember catching crabs by the coast as a child with some bacon attached to a hook, the crabs would grab the bacon and not let go, allowing you to reel them in. Worth a try? Is bacon a good idea to put in the tank? Do intruder crabs like smoked or unsmoked, rindless, Danish?

 

[sparklefuzz]

Ok, I can see a thread appearing shortly entitled "how to catch an intruder crab that sneaked passed security into your marine tank"

He's very shy and bolts for cover whenever there's movement.

I remember catching crabs by the coast as a child with some bacon attached to a hook, the crabs would grab the bacon and not let go, allowing you to reel them in. Worth a try? Is bacon a good idea to put in the tank? Do intruder crabs like smoked or unsmoked, rindless, Danish?

I got 3 of those in my tank, hitchhiked, and they are a good size too. I read the best way to catch crabs is to rest a glass jar against the rock, on an angle, with something meaty in the bottom and leave it overnight. The crab(s) will go in for the food but not be able to climb back out. My question is, what 'meaty' food to use that won't float out of the jar... or the fish get first?! LOL.

Good Luck. Let us know how it goes

 

[Mr Miagi]

I read the best way to catch crabs is to rest a glass jar against the rock, on an angle, with something meaty in the bottom and leave it overnight. The crab(s) will go in for the food but not be able to climb back out.

Yeah, its a goodin'. But what about those crabs not interested in Meaty foods? Not saying dont try it though, because Ive got it to work.

My question is, what 'meaty' food to use that won't float out of the jar... or the fish get first?! LOL.

I tied a prawn to a piece of rock rubble.

You can also try forcing him out. This only works if you know what piece of LR he is in though. Take the piece of rock, and put it in a bucket, covered in tank water. Boil some FW in the kettle. Slowly poor water (not firectly onto the LR) to warm the tank water significantly, but to not burn you to the touch. The crab should exit the LR, searching for better water conditions. You might also see Amphipods, Bristle worms, and Bristel stars leaving too, but you can catch them, and have a "tub" of cool tank water on standby to place "wanted" creatures into.

 

[tmreynolds]

Cheers everyone, he's now made a burrow so i know where he is.

What about the innocent until proven guilty theory, or is that asking for trouble?

I got 3 of those in my tank, hitchhiked, and they are a good size too.

Are they still in there, or did you remove them?

 

[sparklefuzz]

Cheers everyone, he's now made a burrow so i know where he is.

What about the innocent until proven guilty theory, or is that asking for trouble?

I got 3 of those in my tank, hitchhiked, and they are a good size too.

Are they still in there, or did you remove them?

They are still there, and I am adding xenia in about 20 minutes when it has finished dripping... so I am PRAYING they behave... or I will do the prawn in a jar thing. I am going to keep an overly close eye on them...

 

[tmreynolds]

Yeah me too, tried moving some rockwork this afternoon in the hope of finding it but no luck.

 

[tmreynolds]

Could your Porcelain Crab have moulted? How do you know its dead? I recently came across a Xanthid type species in my Nano. They are omnivores, and will take advantage of a food source, so you might want to remove it to a sump, or, alternatively, give it away, or it gets the hammer. Good food for nems, or other fish.

Good news, just seen both my porcelain crabs! So it was a moult . This means there have been no casualties from the intruder crab, hopefully it'll stay that way, because it doesn't want to be caught!

My porcelain crabs are very cool, so I'm happy they're OK