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View Full Version : How bout a blue mithrax crab (emerald crab)


acrodave
11/12/2007, 12:41 AM
It must have been in my tank from day one.But a few weeks ago i saw this guy did not know it was blue but just knew it was a crab. I saw it in one of my more prized acros and was able it snatch it out and take a few pics be four off to the trash

http://reefcentral.com/gallery/data/500/140011DSC01103.JPG

http://reefcentral.com/gallery/data/500/140011DSC01104-med.JPG

http://reefcentral.com/gallery/data/500/140011DSC01106.JPG

green_frogspawn
11/12/2007, 01:17 AM
arent they reef safe?

cfarrow2
11/12/2007, 06:07 AM
Yeah, they're great for bubble algae control. What happened to it? Was it already a goner?

niko5
11/12/2007, 06:19 AM
If you dident throw it away I want it!!!

hypertech
11/12/2007, 07:08 AM
I haven't seen a blue one and I'm guessing that's a molt.

Healthy mithrax crabs don't let you pick them up off a coral. They run and hide in rock crevices.

acrodave
11/12/2007, 10:51 AM
No he was plenty alive.In the book says safe but i dont trust any crab in my tank especially when i find it all up in my coral. Dose any one know what makes crabs,lobster and crayfish turn blue i know its a rare thing

HBtank
11/12/2007, 11:09 AM
cool little crab.

Sux you threw it in the garbage...

fishysteve
11/12/2007, 11:14 AM
senseless killing.

acrodave
11/12/2007, 11:28 AM
OK most of your must not see were i FOUND it in one of my acros. I dont have any algae in my tank so he might have been starving and changed his eating behaviour.And i hold true to that no crab is safe.And yes it was very cool but i have no other tank to put in.People pull out and kill bristle worms and they are good for a tank. I see no difference.

Amoore311
11/12/2007, 11:30 AM
senseless killing.

what exactly did you want him to do? Throw it a "Thanks for eating my Acro Party"?

msuzuki126
11/12/2007, 11:32 AM
No sump?

acrodave
11/12/2007, 11:41 AM
no sump I run a old style tank lots of live rock lots of water flow and heavy protein skimming

fishysteve
11/12/2007, 12:03 PM
Put it in a jar on the bottom of the tank til the next time you go to the LFS and get some credit for it. Don't you work at a LFS?

Amoore311 - You've never had something just crawl across a coral before?

useskaforevil
11/12/2007, 01:04 PM
dude somebody probably wouldve bought that off you. not evil to kill it, but dumb

acrodave
11/12/2007, 01:04 PM
I do work in a fs that were i see how bad crabs can be

HBtank
11/12/2007, 01:18 PM
Half my acros have "crabs" in them.

Anways, there are a few bad ones out there, but emeralds are have been observed to display "acro-crab" behavoir and live in acros, while not harming them at all.

IMO any crab found living in an acro should be left alone if no damage is seen, especially if it is already considered reef safe. The exception may be the hairy guys with blue or red eyes.

From what i have read, the crabs that have really been observed to REALLY harm acros/corals you will probably never see without a flashlight, and definatly not hanging out in them. You will jsut see their damage...

acrodave
11/12/2007, 01:27 PM
Acros crabs live in a symbiosis relationship with the acro. mithrax do eat algae for the most part but like most true crabs will turn predatory given the chance or no food

Blindmelonbob
11/12/2007, 01:35 PM
I'm pretty sure I've read that black pincers = bad crab. Kinda hairy, too. You sure it's a mithrax?

acrodave
11/12/2007, 01:38 PM
It might not be just what it looks like to me . It came from the ocean i did not buy it

twon8
11/12/2007, 02:00 PM
ive seen plenty of crabs hurting acros, without a flashlight.

i dont' think that is a mithrax, i think it's another type; good move getting rid of it.

acrodave
11/12/2007, 02:02 PM
<a href=showthread.php?s=&postid=11167996#post11167996 target=_blank>Originally posted</a> by twon8
ive seen plenty of crabs hurting acros, without a flashlight.

i dont' think that is a mithrax, i think it's another type; good move getting rid of it.

Thank you

Lint_Licker
11/12/2007, 02:34 PM
ALL CRABS are omnivores, no crab is 100% reef safe. ALL crabs are opportunistic feeders, which means if they can catch your favorite fish sleeping, they will EAT it. I caught a emerald crab eating a Abalone, shell in one claw, eating it with the other.

In case all of you people with hermit crabs didnt know, they will hunt down snails and kill them and eat them while they steal their shell for a new home reguardless of how many empty shells you have in your tank for them to move into. If they like the shell your snail has better, they will take it.

I use to believe in emerald until I caught that one. I always had a problem with snails and couldnt figure out what the problem was, my nitrates and everything always checked out fine. Removed all the emerald crabs, and havent lost a snail since!

Lint_Licker
11/12/2007, 02:40 PM
Just for the record, omnivore DOES NOT mean herbivore.

HBtank
11/12/2007, 02:46 PM
<a href=showthread.php?s=&postid=11168237#post11168237 target=_blank>Originally posted</a> by Lint_Licker
ALL CRABS are omnivores, no crab is 100% reef safe. ALL crabs are opportunistic feeders, which means if they can catch your favorite fish sleeping, they will EAT it.


Absolutely untrue,

My bandit acro crabs and porcelin crabs are just a couple examples.

As well, many people have emeralds with easily catchable sleeping fish like fairie wrasse, including myself, and have no problems with "fish eating". So stating they "if they can, they will" is also false.

Your tank souunds like it was underfed and not established. JMO.

goreefer
11/12/2007, 02:49 PM
Too bad it wasn't a little bigger, bring some water to a boil, melt some butter, um, that sounds like some good eattin...

acrodave
11/12/2007, 02:50 PM
Porcelin crabs are not even true crabs they are lobsters

HBtank
11/12/2007, 03:04 PM
Yeh, because we all know lobsters are reef safe.. good point :rolleyes:

They are not "lobsters" at all. If you really want to go the nit-picky route...

They are MUCH closer to hermit crabs than lobster, and closest to "squat lobster" which is only close to "true lobster" by the common name.

HBtank
11/12/2007, 03:04 PM
double post

TWallace
11/12/2007, 04:04 PM
I'm pretty sure he's right in saying that porcelain crabs are actually lobsters. I've read that somewhere else as well.

I've witnessed emerald crabs picking polyps off stylophora and a pipe organ coral (2 different crabs). In both cases, I left the crab alone and the coral showed no visible damage within a day. I have several firefish and a fairie wrasse that don't get eaten by emerald crabs at night, so I don't mind them in my tank.

The crab pictured has black claws though, which makes me think it's not an emerald crab.

acrodave
11/12/2007, 04:31 PM
I may have missed named it as a emerald crab. But just for sake of argument to quote delbeek/sprung vol.1 the reef aquarium about mithrax...."they are excellent herbivores and most important in the control of algae growth in the natural environmrnt.In a small aquarium's however they can be a pest they should be removed from the aquarium since they can grow large and may eventually feed on corals and fish"

ginger7286
11/12/2007, 04:42 PM
I found several Green and Red Mithrax crabs in my tank. Yea they are suppose to be reef safe...I found them eating everything but the algae including other crabs. Let's just say I brought them to my LFS and traded them. The hairy little black clawed crabs are usually Gorilla Crabs BAD crabs and nothing in the tank thinks they are tasty.

LeslieH
11/12/2007, 04:59 PM
Couple of things --

Acrodave's blue crab isn't a Mithrax. It's in the same family but another genus, maybe Liomera, Etisus, something like that. Unlikely to be a herbivore and very likely to be a typical opportunistic predator/omnivore.

A lot of crabs change their diets as they grow. Crabs that are harmless when small can become quite destructive when large. Crabs also have individual preferences in food. Emerald crabs don't read so they don't know that many books say they should be herbivores.

"Black-tipped claws = bad crab" is a reef myth. Claw color has nothing to do with eating habits.

Porcelain crabs, hermit crabs, and squat "lobsters" are all in the same infraorder Anomura. Lobsters belong to Palinura, true crabs belong to Brachyura. Porcelain crabs are either detritus feeders or filter feeders.

Acro crabs are true crabs. They're thought to eat detritus, mucus & dead cells from their hosts, and some probably eat polyps as well. In nature that's not a problem; in tanks the acro's growth may be slow enough that it could be. Overall though, acros with acro crabs grow faster & healthier than those without the crabs.

chrisalmand
11/12/2007, 05:02 PM
Really dumb to kill it, why not just drop it off at the fish store?

acrodave
11/12/2007, 05:21 PM
It was in the middle of the night and it was my day off today. And like most pepole i dont go to my job when i dont have to. And if you realy want to be ethical about me killing a crab then you should not keep a fish/reef tank.You know how many fish and corals die in transit just to get the one you want. So i dont think i should b called "dumb". Do you think it is good to throw a damsel in a take full of ammonia burning it gills and high nitrate i sure that is good for them

awcurl
11/12/2007, 05:26 PM
<a href=showthread.php?s=&postid=11166857#post11166857 target=_blank>Originally posted</a> by fishysteve
senseless killing.

Sounds funny coming from someone who's profession experiments with animals daily!(Occupation: Pharmaceutical Research & Development):confused:

chrisalmand
11/12/2007, 05:45 PM
I'm not saying you're dumb, I am saying killing the crab was dumb.

Lint_Licker
11/12/2007, 06:00 PM
<a href=showthread.php?s=&postid=11168332#post11168332 target=_blank>Originally posted</a> by HBtank
Absolutely untrue,

My bandit acro crabs and porcelin crabs are just a couple examples.

As well, many people have emeralds with easily catchable sleeping fish like fairie wrasse, including myself, and have no problems with "fish eating". So stating they "if they can, they will" is also false.

Your tank souunds like it was underfed and not established. JMO.

Apparently you havent had an aquarium long enough or have enough experience to be giving anybody advice. Dont be quoting something you heard cause you dont know if that person was quoting a crazy person who has no clue whats going on. I am speaking from FIRST HAND EXPERIENCE, not something I read somewhere or heard somewhere. So I suggest you do some research before you go and pretty much tell somebody they are lying or what they are saying is untrue. Show me some proof they are reef safe, and dont go quoting some website TRYING to sell you something.

Lint_Licker
11/12/2007, 06:04 PM
Another thing, people like you HBtank are the ones who give RC a bad rap and make people look for other forum or start their own.

mr slinky
11/12/2007, 06:14 PM
<a href=showthread.php?s=&postid=11168332#post11168332 target=_blank>Originally posted</a> by HBtank
Absolutely untrue,

My bandit acro crabs and porcelin crabs are just a couple examples.

As well, many people have emeralds with easily catchable sleeping fish like fairie wrasse, including myself, and have no problems with "fish eating". So stating they "if they can, they will" is also false.

Your tank souunds like it was underfed and not established. JMO.

i think ya should buy a book on crabs cause your actually incorrect mate !!!!:lol:

mr slinky
11/12/2007, 06:16 PM
<a href=showthread.php?s=&postid=11169650#post11169650 target=_blank>Originally posted</a> by Lint_Licker
Another thing, people like you HBtank are the ones who give RC a bad rap and make people look for other forum or start their own.

Good one all in one , no wonder 3reef ****s all over this site!!!!:eek:

Fishkeeper101
11/12/2007, 06:17 PM
Okay, im a little scared to put my 2 cents in here, but here it goes.

I have not worked with warm water crabs very much, but with my experience with raising temperate crabs in a very large school aquarium, I have found that they will eat anything offered to them, or at least try it.
However, I have noticed that what the crabs generally eat (using temprate examples, a kelp crab generally eats kelp, cancer crab tend to be a good scavenger) , and how large they are does effect how voraciously they go after something.
We had 2 large Kelp Crabs and a medium cancer crab in this aquarium for a very long time. The kelp crabs, nearly always kelp eaters, would also eat squid and other meats if offered, and we were running low on kelp. The cancer crab, would eat anything. And he voraciously ate everything in the tank that he could catch.
Im sure thats where some of our fish "disappeared" to.

I guess what I'm trying to say is that, in my experience, yes, crabs are opportunistic, and will eat anything. But, I would assume that if a generous amount of thier choice food is offered, you would see them chose that over chasing down fish.

Taking what i have observed in temprate reefs, I would assume mithrax crabs are not reef safe in the truest sense of the term. they will be opportunistic, but if you keep them well fed, you probably wont see them chasing down fish to eat.
I certainly haven't had any issues with mine.

K, just my 2 cents.

mr slinky
11/12/2007, 06:20 PM
acro dave ya did what ya had to do good stuff mate!!!!

HBtank
11/12/2007, 06:34 PM
<a href=showthread.php?s=&postid=11169650#post11169650 target=_blank>Originally posted</a> by Lint_Licker
Another thing, people like you HBtank are the ones who give RC a bad rap and make people look for other forum or start their own.

At least I do not resort to personal attacks. :rolleyes:

I am sorry you feel the need to attack me and not the subject matter.. And I hardly see how sharing an opinion makes RC a worse place...

But the fact is your post is still untrue. It is not true that "ALL crabs" will resort to predatory behavoir on fish.

It is far from certain, as your post states

acrodave
11/12/2007, 06:34 PM
Thank you

HBtank
11/12/2007, 06:39 PM
<a href=showthread.php?s=&postid=11169715#post11169715 target=_blank>Originally posted</a> by mr slinky
i think ya should buy a book on crabs cause your actually incorrect mate !!!!:lol:

On what points?

*looks at crab book*

Please show me...

mr slinky
11/12/2007, 07:02 PM
LMAO mate get a grip ya wrong just face it no personal attacks either !!! thats why we are here , trying to discuss not give some crap about what he shoulda done ..... well read the book mate and prove me wrong!!!!

mr slinky
11/12/2007, 07:08 PM
<a href=showthread.php?s=&postid=11169951#post11169951 target=_blank>Originally posted</a> by HBtank
On what points?

*looks at crab book*

Please show me...

well !!!! are ya reading??? prove us wrong dood???

**waiting**

mr slinky
11/12/2007, 07:11 PM
<a href=showthread.php?s=&postid=11169753#post11169753 target=_blank>Originally posted</a> by Fishkeeper101
Okay, im a little scared to put my 2 cents in here, but here it goes.

I have not worked with warm water crabs very much, but with my experience with raising temperate crabs in a very large school aquarium, I have found that they will eat anything offered to them, or at least try it.
However, I have noticed that what the crabs generally eat (using temprate examples, a kelp crab generally eats kelp, cancer crab tend to be a good scavenger) , and how large they are does effect how voraciously they go after something.
We had 2 large Kelp Crabs and a medium cancer crab in this aquarium for a very long time. The kelp crabs, nearly always kelp eaters, would also eat squid and other meats if offered, and we were running low on kelp. The cancer crab, would eat anything. And he voraciously ate everything in the tank that he could catch.
Im sure thats where some of our fish "disappeared" to.

I guess what I'm trying to say is that, in my experience, yes, crabs are opportunistic, and will eat anything. But, I would assume that if a generous amount of thier choice food is offered, you would see them chose that over chasing down fish.

Taking what i have observed in temprate reefs, I would assume mithrax crabs are not reef safe in the truest sense of the term. they will be opportunistic, but if you keep them well fed, you probably wont see them chasing down fish to eat.
I certainly haven't had any issues with mine.

K, just my 2 cents.

Bravo read it hb tank!!!!!

HBtank
11/12/2007, 07:13 PM
I thought aussies spoke english?

Lint_Licker
11/12/2007, 07:14 PM
+2 on reading that

.....Im curious what book he's reading, and wonders if it was wrote by a certain english lit major, hahaha

edit...I was agreeing with slinky.

mr slinky
11/12/2007, 07:19 PM
<a href=showthread.php?s=&postid=11170240#post11170240 target=_blank>Originally posted</a> by HBtank
I thought aussies spoke english?

ya wanna get racist ya ****er!!!!!

mr slinky
11/12/2007, 07:22 PM
quick edit there HB tank misspelt english aye?????LMFAO

Lint_Licker
11/12/2007, 07:22 PM
*waits for this to get closed, hahahaha

HBtank
11/12/2007, 07:23 PM
<a href=showthread.php?s=&postid=11170249#post11170249 target=_blank>Originally posted</a> by Lint_Licker
+2 on reading that

.....Im curious what book he's reading, and wonders if it was wrote by a certain english lit major, hahaha

+3 on either of you guys reading period..

I think you skipped the books and just watched this:

http://ecx.images-amazon.com/images/I/71G749DQ93L._SS500_.gif

Lint_Licker
11/12/2007, 07:24 PM
Who is making personal attacks? It looks like you are but you're making a fool of yourself.

Im not going to post anymore on this because apparently you are to ignorant to understand any of it anyways.

HBtank
11/12/2007, 07:27 PM
It was quite obvious that neither of you read my posts or intended to discuss this at all.

Anwyays, have a nice day.

mr slinky
11/12/2007, 07:27 PM
Now that just proves how much of a wanker you are !!! Can even have a discussion without getting racist or snide remarks like that
!!!

acrodave
11/12/2007, 07:28 PM
I dont want my thread closed... so dose any one know what makes them blue in the first place. I know that blue lobster are hard to come buy

mr slinky
11/12/2007, 07:29 PM
you should really think about sticking to the subject and claim that you are wrong!!!!But we all know you are a loser now so...

:rollface: :rollface: :rollface: :rollface: :rollface: :rollface: :smokin:

mr slinky
11/12/2007, 07:32 PM
acro dave there are many coloured crabs outthere dood ask HB tank !!! he seems to know whats going on

acrodave
11/12/2007, 07:36 PM
I want to go to australia, They have they kind of attidue i like lol

HBtank
11/12/2007, 07:36 PM
<a href=showthread.php?s=&postid=11170363#post11170363 target=_blank>Originally posted</a> by acrodave
I dont want my thread closed... so dose any one know what makes them blue in the first place. I know that blue lobster are hard to come buy

Genetic defect, similar to albinism.

"Their research, which was conducted at the University of Connecticut, discovered that a genetic defect causes a blue lobster to produce an excessive amount of protein. The protein wraps around a small, red carotenoid molecule known as as astaxanthin. The two push together, forming a blue complex known as crustacyanin which gives the lobster shell a blue color. "

mr slinky
11/12/2007, 07:39 PM
BRAVO to the wanker in california ya know who you are too!!!:lol:

Runner
11/12/2007, 07:39 PM
I pulled a 2' long zoanthid-, xenia-, snail-, and gsp-eating worm out of my tank, took pictures, then disposed of him in an inhuman manner because it made me feel better and the trouble in keeping him alive long enough to ship the dirt bag to somebody who would want to acutally keep him was not worth the pain in lost corals he caused me. So I can relate to acrodave. Sure, my critter wasn't cute and cuddly like his is, but it is what it is. Strange that people would be so critical of him for offing a parasite.

mr slinky
11/12/2007, 07:41 PM
<a href=showthread.php?s=&postid=11170448#post11170448 target=_blank>Originally posted</a> by Runner
I pulled a 2' long zoanthid-, xenia-, snail-, and gsp-eating worm out of my tank, took pictures, then disposed of him in an inhuman manner because it made me feel better and the trouble in keeping him alive long enough to ship the dirt bag to somebody who would want to acutally keep him was not worth the pain in lost corals he caused me. So I can relate to acrodave. Sure, my critter wasn't cute and cuddly like his is, but it is what it is. Strange that people would be so critical of him for offing a parasite.

My whole arguement to HB tank we are here to learn and not rubbish anyone can rubbish people!!!!

mr slinky
11/12/2007, 07:43 PM
<a href=showthread.php?s=&postid=11170430#post11170430 target=_blank>Originally posted</a> by acrodave
I want to go to australia, They have they kind of attidue i like lol

any time bro we dont put people down we strengthen !!!

Like a few american friends i have!!!!

acrodave
11/12/2007, 07:46 PM
<a href=showthread.php?s=&postid=11170432#post11170432 target=_blank>Originally posted</a> by HBtank
Genetic defect, similar to albinism.

"Their research, which was conducted at the University of Connecticut, discovered that a genetic defect causes a blue lobster to produce an excessive amount of protein. The protein wraps around a small, red carotenoid molecule known as as astaxanthin. The two push together, forming a blue complex known as crustacyanin which gives the lobster shell a blue color. "

Thank you

mr slinky
11/12/2007, 07:51 PM
<a href=showthread.php?s=&postid=11170432#post11170432 target=_blank>Originally posted</a> by HBtank
Genetic defect, similar to albinism.

"Their research, which was conducted at the University of Connecticut, discovered that a genetic defect causes a blue lobster to produce an excessive amount of protein. The protein wraps around a small, red carotenoid molecule known as as astaxanthin. The two push together, forming a blue complex known as crustacyanin which gives the lobster shell a blue color. "

BRAVO TO YOU !!!! Why couldnt you say that straight out instead of giving him crap about it???? very uncool dood
very uncool

geo
11/12/2007, 08:33 PM
Closed.