Murdering Mithrax Mofo

[Juck]

A couple of weeks ago I increased the lighting cycle in my 75g to get my clowns spawning. I got some small patches of hair algae on the sand, I assumed because of the extended photoperiod.

At this time, the tank contained nine fish, a scooter dragonet and mated pairs of firefish, green chomis, pajama cardinals and Gold Stripe Maroon clowns. The tank is well established and there have never been any disease problems.

I got a couple of emerald Mithrax crabs from my LFS and they cleared up the hair pretty quickly.

About a week ago, my male cardinal went awol,,,, he wasn't in their cave and he wasn't brooding at the time (he usually hides during the day when brooding) ,,,, I figured he'd just died, though I never found his body,, just figured the hermits were having a feast somewhere.

This morning I'm walking past the tank and notice the larger mithrax walking around with something in his claws,,, oh great,,, it was a firefish, or rather half a dead firefish (the male). The firefish was fine last night,,,, he was watching over a bunch of eggs in their cave.

I'm assuming I have a 'bad' crab here,, nothing has ever gone missing in this tank before,, I don't know what else to think. This was a fantastically interesting tank before these deaths.

I'm going to take both crabs out today. I guess there really is no such thing as a safe crab. Has anyone else had a problem with a mithrax eating fish? Or am I just lucky?

Snapped a pic of the swine enjoying his breakfast,,,,,

 

[wade1]

You positive nothing else is killing the fish? All crabs are certainly scavengers (and many are opportunists) and will eat something thats dead/dying without blinking.

I've heard mixed results with mithrax (better results with Sally Light Foots) though... so possibly.

Wade

 

[Unarce]

A friend of mine put one of those in his clown tank and they all began swimming in the corner.

Descriptions of mithrax crabs usually includes their tendency to go after small fish.

 

[Juck]

Hiya Wade,

I can't think of anything,,, there's been no new LR in the tank for a year,, the only interesting HH I ever saw on the rock was a peanut worm. The only other inhabitant is a blue linckia.

There is a carpet anemone in there but it isn't very big and certainly couldn't swallow a full-grown cardinal.

The big female maroon clown can get a bit aggressive when she has eggs but nothing like this. It's a really peacful tank,,, most here would probably think it boring.

There may be something lurking in the rocks I suppose,,, maybe a big bristleworm,, though I've never seen one.

 

[taikonaut]

Sad to hear that the firefish got nailed when watching after the eggs.

I will not put these pigs in my tank anymore due to my experience with them on my baby T. max. clams. Good algae ripper, however, but just too much risk.

 

[Juck]

Hi Reefnutz,

You're right,, I should have researched properly. Lousy $5 crab really messed up my 'love' tank.

 

[PopeShawnPaul]

I'm getting deja vu. It's definitely the emerald crab from the sounds of it. I have owned many in the last 6 years, and have caught about half of them going after something they shouldn't. About 4 years ago, I caught an emerald I purchased catching one of my clownfish. He hid in a cave, then when the clown went by, he rushed out and grabbed him. I quickly got in there and saved him before he pulled him back into the hole. It was close though. Needless to say, that emerald got a trip back to the lfs. I don't have any of these crabs anymore. I also had one eat my goby. And I suspect one got my molting shrimp as well. Nasty little buggers in my opinion. If you really want some, only buy the smallest ones you can find with the smallest pinchers. They seem to be fairly harmless.

 

[cdeakle]

I have 4 emerals that I have had in my tank for over 2 years. They have never harmed anything unless it was already dead.

One time I found them eating a cleaner shrimp but he was already dead laying on tyhe bottom of the tank.

Luck of the draw I guess...

 

[Jolieve]

I had an emerald mithrax kill one of my cleaner shrimp on introduction. He got a one way ticket back to the lfs. It sucks, because these crabs mow bubble algae down like it's going out of style, but.. it's not worth the risk to my livestock to keep them.

Good luck,
J.

 

[wade1]

Keep in mind as well that there are many species of mithrax, some that even grow to 6" in length! One person's good experience might just be a different species in the end.... who knows.

Wade

 

[cdeakle]

true true....

 

[meinkfr]

I have two in my 55 gal. One is almost 2 inches big. He liked to snap at any fish that would get close enough. He never got lucky,(must be to slow). But never seemed to go on the hunt, I presumed it was a territory thing. Small one is real subdued.

 

[Juck]

Thanks all,,, didn't manage to catch him today,,, to add insult to injury he's been upside down in the firefishes' cave all afternoon eating the eggs.

He's bound for the 37g 'rejects' tank in my office,,a place for all the marine lifeforms that just didn't quite work out. There's a mental coral beauty in there that'll put him straight, by God.

 

[Jolieve]

A mental coral beauty? I'm not sure if I want to hear this story or not. Share!

Rejects tank hm? This might be for a whole other thread... but what gave you the idea to set that up and what's in there? Just curious.

J.

 

[Jolieve]

Oh... one more thing... it might be easier for you to catch him if you can pick up the rock he is on, and place it in a separate bucket filled with water that has a slightly lower specific gravity (not much lower, just a little bit, maybe 1.020 instead of 1.022) and wait for him to drop off the rock. That's how I caught mine...

Not sure that this is the greatest idea in the world, but... it worked once. *chuckle*

Good luck catching him,
J.

 

[Juck]

Hi Jolieve,

Well, the coral beauty had some 'authority issues',,, he was really aggressive with his tankmates in my 90g,, he nipped at every coral and he went absolutely bonkers whenever someone put their hand in there,, racing round the tank and banging against the sides.

The rejects tank also has 3 aggressive yellow-tail Blue damsels that I used to cycle another tank nearly 2 years ago,,,, a one-eyed pajama cardinal that I got for a dollar from the LFS (they were gonna feed him to a grouper for god's sake,, I had to take him,, but damn,, he's ugly),,,,, and a sargassum fish that someone bought me because it looked 'cool' (it isn't cool at all,, it's just a big mouth,, like Joan Rivers with fins).

The tank also contains all the crappier pieces of live rock I've received over the years.

I don't like taking things back to the LFS,,,,I get attached to my animals and someone else might not take care of these misfits,, after all, they didn't ask to be yanked out of the ocean and I figure they deserve to live out their lives,, it's certainly an interesting tank to watch.

 

[cdeakle]

and a sargassum fish that someone bought me because it looked 'cool' (it isn't cool at all,, it's just a big mouth,, like Joan Rivers with fins).


:lol: :lol: :lol:

 

[Anonymous]

Thanks all,,, didn't manage to catch him today,,, to add insult to injury he's been upside down in the firefishes' cave all afternoon eating the eggs.

He's bound for the 37g 'rejects' tank in my office,,a place for all the marine lifeforms that just didn't quite work out. There's a mental coral beauty in there that'll put him straight, by God.

A "rejects" tank? Oh, this has to be good!
Better'n the "grab bags" one of our exporters from Africa would send us!
(Although.. I remember getting a GORGEOUS Synodontis cat.. not S. eupterus or S. angelicus.. but similar.. O! How I wish I still had all my books.. damned ex-boyfriend. :evil

 

[Jolieve]

Your rejects tank actually sounds like a really good idea. I hated taking the mithrax back to the lfs, I actually like crabs, they are neat critters. But I just don't want to lose any of my other livestock to them.

The one I had will always have a place in my heart for being the Charles Atlas of crabs... it wasn't funny at the time, but the day he killed my cleaner shrimp, he stood up on the end of the rock and posed his claws up, then back down.. reminded my husband of Charles Atlas.

 

[shr00m]

i have 4 or 5 mithrax crabs in my tank, they never bother the fish, but if the fish swim close they open there claws, but in defense.... my clown got a big scratch on his side about a week ago and i thought it was a mitrhax that did it, but i recently found a brown/orangeish crab with black claws that looks like a mithrax only not with cupped claws.... i really think this crab is the one that attacked the clown, who recovered by the way, i know which live rock this crab lives in and if i find out hes a fish killer i probally will try to get him out.