View Full Version : Crab ID Please

07-10-2006, 09:49 PM
What kind of crab is this one?, good?, bad?....the color on the picture its accurate.


07-10-2006, 10:49 PM
Kind of hard to see it. I would try to get it out and into isolation until you get a good ID on it.

07-10-2006, 11:33 PM
i agree,
while im not very good at identifying these, there are MANY people here that are great at it. but you will need to get a very clear close up shot to get a positive ID.
try to grab it, and put it in a container to photograph

07-11-2006, 12:02 AM
At first glance it looks like an Emerald Mythrax Crab. But a clearer picture would help nail down a positive ID. Trust me we all know the pain of trying to get a picture of some of the critters in our tanks.


07-11-2006, 06:58 AM
I'm tending to go with johnnyblackheart's opinion on this one. If that's what it is it's an algae eater and safe to keep.

07-11-2006, 09:09 AM
where' wally? lol no serious, i need a a dictonary & a flash light just to make up some words for the lack of crabs i can see!
to me it looks like a stalker picture:D

07-11-2006, 11:31 AM
here V
let me help you out a bit.. ;)

07-11-2006, 05:36 PM
hey hey, theres wally! thanks rob, nice circle job. i bet that was as expensive piece of equiptment..lol

07-11-2006, 10:19 PM
LMAO @ Veriann

Sorry I had to reply to that Rob.......

fat walrus
07-12-2006, 02:38 AM
hey hey, theres wally! thanks rob, nice circle job. i bet that was as expensive piece of equiptment..lol
hey veriann, in america..........we call that expensive piece of equipment............................CRAYON. haha

07-12-2006, 03:26 AM
indeed it is! lol

07-12-2006, 07:39 AM
LMAO blubber. :rotfl: That's also known as a "Gotch ya" :eek: in America, veriann.

bmwaaron, no need to apologize for laughing at anyone on TR. By neccessity, we all have broad shoulders. It's just that veriann very often gives us reason to LMAO. It's cause he lives upside down, don't ya know. Some times you have to shout at him to get his attention. Like, Hey, V, how you doin down there? You got a tinnie coolin for me? :cool:

07-12-2006, 07:49 AM
dont let the upside thing throw u, it works out alright when the ladies are walking by :p

07-12-2006, 08:04 AM
You see, bmwaaron? If you rattle his cage veriann responds quickly.

LMAO, rolling on the floor, side splitting, tears and everything, LMAO! That's it. Now you've done it V. I want to come to Aussie Land.

07-12-2006, 12:12 PM
To be honest its the first time I seen it, so I have no idea on how grab it for a better pic.

fat walrus
07-12-2006, 06:21 PM
put out some food right out in the open.

07-12-2006, 06:55 PM
gorrilla crab? i have those guys in my tank also.

08-13-2006, 10:01 PM
Yes, this is a gorilla crab. I discovered one in my tank today, but it evaded me when I tried to remove it. Are these crabs dangerous to my livestock or corals?

I dunno why the hell all these hitchhikers are showing up now, I havent put a rock in the tank in over 5 weeks. But all the sudden, I am finding something new like this every time I turn around.

08-14-2006, 07:09 PM
I read it before that it's bad, so I just trap all of them. They usually come along with Vanautu rocks (I mean ALOT of them with the rocks, of course they can come with any type of LR)

08-14-2006, 07:31 PM
how do you trap them?

08-14-2006, 07:32 PM

You want to keep a lookout for Gorilla crabs (xanthid species). These pesky buggers are predators that can cause damage to your reef, eating anemones, clams, and anything else they can get their claws around. They might look cute when they're small, but it's just not worth putting them into the tank. If you really want to keep them, you could put them into your sump/fuge (if you have one).

The sure-fire way to spot one of these is to look for the black tips on their claws. As they get larger, they become quite "hairy" all over. Take a look at the catalog of organisms for pictures of other "good crabs" that may hitchhike on your rock. You can smash these guys pretty easily using a chopstick.

Gorilla Crab: Bad Crab!

Porcelain Crab: Good Crab!

Most other crabs are ok to keep in the tank, but beware that as they grow larger, you may find some crabs munching on sponge or starfish. To determine if a crab is "reef safe", take a look at the size and shape of the claws, as they are usually good indicators. If the claws are large and pointed, it's most likely a predator. If the claws are smaller and have blunt tips, then it's usually a herbivore and reef safe.

This Info was copied from http://www.tampabaysaltwater.com/thepackage/watchout.html

If you take a smooth plastic or glass cup leaning up aginst your LR with some food in it when the crab goes in for the food the glass will tip up and the crap will not be able to climb out you can then move it to your sump/fuge or as you see fit.

08-14-2006, 08:42 PM
Would this be a gorilla crab?


I used to know where he lived, but he moved. eek! I have noticed that my hermit crab population is hardly anything. I had over 100 hermits and I think he has slowly picked them off. :( That photo is a molt by the way.

08-15-2006, 01:18 AM
Looks more like a shag carpet crab. :lol: I have found a few small crabs (smooth body no hair) in my tank most are too small to see the claws. I call them rock crabs because thats where they seem to be when I see them. I did find a fairly large one with a white body and very pink claws he was very cool.

08-15-2006, 01:13 PM
Yeah, that one is really hairy - even on the carapace. The one I have spotted is just like in the first photo. Hairy legs, black claws, kinda alabaster colored but really camoflauged.

I saw the little bastard again last night, he evaded me on the first attempt. The second time, I went in with a wooden bamboo skewer. I didn't impale it (Figured if I can't capture it and end things humanely, then I am going to go after him like I'm the predator!) but I did get some leverage on it. When I removed the skewer, he moved off, albeit not as quickly as before.

My wife witnessed the whole thing, she says I didn't get squat. She's mocking me now. This thing is gonna die.

08-15-2006, 08:16 PM
Would this be a gorilla crab?


I used to know where he lived, but he moved. eek! I have noticed that my hermit crab population is hardly anything. I had over 100 hermits and I think he has slowly picked them off. :( That photo is a molt by the way.

Yes it is:|

09-12-2006, 01:43 PM
Anyhow... an update on my little bastard!

For weeks now, I have been trying to catch this guy. I thought I almost had him a time or two, but usually he stays just far enough away that I cannot reach him. If I *can* reach him, it's in a manner that will take some time to jockey around rocks and such, and he always scurries away laughing.

Well, this morning I got the last laugh. Not permanently (!!) but I ended up taking one of his big pinchers. He is TOUGH! I thought for sure I had squished the life out of the little everything-vore but nope, all I got was a pincher for my troubles. Well, at least he understands that I'm serious now. :D

I'll post a photo if I can later.

It's a shallow victory, no doubt... but I'll take what I can get where he is concerned. What I need is a tiny speargun. :mad:

09-12-2006, 01:51 PM
Congrats Jeff, hahaha but sorry to let you know by its next molding, your enemy will have its craw grow back :)

Have you try the glass bottle trick to catch it yet? Use a glass bottle (jam glass etc..) tilted it at an angle like 45 degrees. Put a large piece of food in. You might have to cover the opening with egg crate or the like if the opening is large enough for your fish/shrimps to go in and steal the food. Put the bottle near the hole that the crab lives. I caught mine that way, might take a few days but it sure beats a month ;)

09-12-2006, 02:02 PM
It's not going to live long enough to molt.

09-12-2006, 02:04 PM
But yeah, sorry... I am going to make a trap for it this weekend. Hopefully I won't get it suck in there with other emerald crabs, but that's the risk I suppose.

09-12-2006, 08:07 PM
Go! Go! It's man vs. crab!

12-24-2006, 03:16 PM
Well, I finally got my hands on this little crab (and actually removed him from the tank).

As I now have a sump (for my prop tank) I dropped him in there until I have a good ID.

Here are some photos. I would love to get your opinions.

12-24-2006, 05:03 PM
Those claws are very thick and prominent which is usually an indication of a crushing behaviour.... bad for the tank. I would keep him out.

12-24-2006, 05:44 PM
Renee, I agree with your assessment. However, he has been in my display tank for over 4 months with no (observable) detrimental effects. Also, compared to the pinch put on my by my Emerald crab when I removed him... he's quite strong, but a pacifist! :)

So while I have no plans to return him to the tank, I still really want to know what he is!

12-24-2006, 06:39 PM
I'll ask around and see what I can find out... or not find out.

12-25-2006, 06:42 AM
I keep a crab free reef. I have just watched too many of them kill my livestock particularly the snails. (Even with extra shells for the hermits.)
I have also read that the general rule is if they are hairy or have black tipped claws they are not reef safe. I'm not sure how true this is since I remove all crabs but your guy seems to match both watch out rules. Keeping him in the sump may be a great idea. Keeps him alive but in a place where he can do no damage. Any I find go to the lfs, but I am happy to hear of anyone removing them humanely. They are only doing what is natural and it's not their fault they are opportunistic feeders.
As to the appearing several weeks after the rock was added, I have seen this several times. I have some lr in my qt tank that has been there since June. I still see mystery critters appear. I'm just glad it is in the qt instead of the reef since it makes them much easier to remove.

12-28-2006, 11:29 AM
It's likely Pilodius granulatus (family Xanthidae).

12-29-2006, 12:29 PM
I'm just glad it is in the qt instead of the reef since it makes them much easier to remove.

Yeah... I don't currently QT anything, but the more I keep my small reef, the more I know I really *should* do so.