weird crab in our tank please help

[Myaem]

ok so denise and i have had this tank for about 4 months now. we always check our water levels and do everything we can to keep them perfect. our corals are growing and everything seems fine. recently, we saw our serpent starfish missing 2 of his legs and looked beat up. so we took out our emerald crabs (3) and brought them back to the pet store. tonight during a regular feeding we notice something moving around in the back of our tank. we take a look and see a pretty big black/grey crab with red eyes. we definitely never bought this thing and we think he is responsible for the brutal murder of our serpent starfish. does anybody have any information as to what this thing might be and if it should be removed from the tank. please help us out.

thanks
matt & denise

[Dentoid]

Hard to tell without a picture, but large crabs, generally, are not reef safe. Although, most, if not all crabs, are opportunistic feeders, the Emerald crab is mainly herbivorous.

As a general rule of thumb, (and there are exceptions to every rule) smooth shelled crabs are ok and hairy shelled crabs are not. There are many reefers that will say no crabs whatsoever in a reef, but I'm from the school of thought that they add another dimension of diversity to the reef tank. They are such good scavengers that they will keep your tank clean, especially in the nooks and crannies that can not be reached by ordinary means.

Also, starfish are very sensitive to sudden changes in the water chemistry. Although, Serpents are surprisingly hardy. Have there been any sudden changes in your reef's water parameters lately?

[Myaem]

there have been no sudden changes in our water. we do a 3 gallon water change every sunday and our levels have been very consistent. also, i forgot to mention that we had a blenny that disappeared in about a week

[Myaem]

this is a picture of the suspect himself

[kathywithbirds]

That looks like a bad crab to me. he just looks like a fish eater.

[cracker]

Myaem, Please consider getting that crab outta there! That pretty big crab is the top suspect concerning the missing blennie & murder of the stars.

[Dentoid]

Hairy, not good! It was a good thing that you got it out of your reef. How big is that sucker?

[AngelLeah1981]

Man, I just had to read this thread because of the title. It made me laugh although I know what you're going through is not funny. What I'm wondering is where the heck did it come from !?!?
Leah

[Rcpilot]

mmmmmmmmmm dinner!!

Generally speaking--- a hairy crab is a bad crab.

[Melanie]

Nice job hunting and capturing that crab! He does look like a bad crab. They come from your live rock. Those hardy suckers can get in a hole in the LR and you never know they are there until this happens.

[Myaem]

that is exactly what happened he was in a hole in a piece of LR that we bought and never really came out. he's out now though, thanks to all of you guys for the advice

[Witfull]

its a gorilla crab. they come in on live rock and are EVIL,,,,i mean they are the posterchild of CAE!

good job and i think you merit membership in Crabs Are Evil~

[MrB]

WoW i found one of those little buggers in my uncured figi rock i just bought!! he got speared an tossed in the open fire lol

[Cal Native]

hmmmmm,,, smooth good, hairy bad

[Frankie]

Myaem, could you come over and get the two in my tank out? I have been trying for over a year now and still can't get the little buggers! Mine are not gorilla crabs but just as bad imo.