Blue legged hermit murder. Case #6

[derek_s]

So maybe 2 weeks ago I added 10 BL hermits to assist in cleaning. They gave the algae a run for it's money, but then, I noticed some little blue legs floating. Dead. Now, weeks later, I can only count 4, and there are previously occupied shells everywhere. They had plenty of other shells to grow into, so I'm not really sure what's going on?

My only stock is some frags, 3 cleaner shrimp, 2 percs, and 1 engineer goby. Do BL's kill each other frequently? Or is there something else...?

 

[matttvi]

Where did you get your LR from?

Do you hear any clicking or snapping noises from the tank?

 

[flyingarmy]

MattTVI;136832 wrote: Where did you get your LR from?

Do you hear any clicking or snapping noises from the tank?

On that note...

Are the shells left over cracked or have holes in them?

Could be a mantis shrimp.

 

[derek_s]

No, no clicking or anything that would indicate pistol/mantis. My LR came from LiveAquaria, mostly. A few other pieces from CBay and Atlantis, and my sump rubble from Marine Fish.

Hmm... would it be possible for a mantis to migrate up a return line alive? Could it survive a Mag 5 voyage?

 

[derek_s]

The reason I ask is because Marine Fish mentioned a mantis in the rubble tank, just in casual conversation. I didn't take much note.

BTW, most of the shells don't appear broken. I will try to pull them out tonight for a closer look.

 

[glxtrix]

no i don't think so. if you don't see any holes in the shells, its possible it's just survival of the fittest. Crabs grow and will bully other crabs out of shells to make room for theirselfs. Part of the live cycle I guess.

 

[gwhiz]

You may want to get some extra shells in the tank so they can pick an unoccupied one rather than have to evict somebody else. I've heard that you can get a bag of shells at craft stores (Michaels) for cheap, but I haven't bought there.

 

[derek_s]

Yeah, that's what CBay told me. An employee said theirs only seem to live 8 months or so, usually becoming victims of blue-on-blue crime before dying of old age.

 

[sagent3000]

i have had that happen before i bought like 50 crabs and over the next few days they had killed all the snaill took their shells and then killed the other crabs with the shells they liked. i think i am the only one that has blue legs running around in turbo snail shells.

 

[liverock27]

I have had the same problem over the past few weeks losing 3 out of my 5 hermits. They are getting pulled out of the shell by something. They are not being eaten by anything, but it looks like the other hermits just want their shell.

 

[glxtrix]

if you buy new shells remeber 1 thing. Buy shells with larger openings. The larger the shell really doesnt mean all that much. The crabs body isnt really that big once out of the shell. So a larger opening will be more appealing than a huge shell.

 

[gwhiz]

Barbara;136858 wrote: That just made me laugh so hard! I love the "blue on blue" crime.

Are you sure you're not seeing molts? If the hermits have been eating a lot, perhaps they've molted and moved to another shell? (I'm pretty sure they molt.......)?

Hermit's don't really molt. When crabs molt they shed the shell they're in and hide until they grow a new one. Hermits don't grow their shell..they just find or steal a bigger one when they outgrow what they're in.

 

[platyplakia]

Hermit crabs do molt. Mine do all the time. It has nothing to do with their shell, like Geehh said, but they molt just like other crabs. It looks pretty much like the part of the crab that comes out of the shell with a little bit of white tissue from the part that hides in the shell. My first guess would have been molts that you're seeing. They're pretty small, so there may be some crawling around on the rocks and you just can't see them. Best of luck.

 

[reeferjw]

I believe all crustaceans molt.

 

[cameron]

Yes hermits molt and yes the kill each other for their shells. Often a crab molts and needs a bigger shell other times he sees an easy meal and a new pretty shell. The molts look like hermits out of their shell.

 

[derek_s]

I considered that, but I'm pretty sure they're not molts. Last night I saw more carnage, so I used my feeder to suck it out and examine it. It didn't look like a molt, as the crab was still mostly intact (legs, head, eyes, feelers...) The only thing missing was the meaty tail-end portion that stays in the shell. The delicious part, I assume.

 

[platyplakia]

That's exactly what a molt looks like. Just the front part without the "meat". My money says you're alright here.

 

[cameron]

You can't tell the difference easily between a molt and a dead crab except the mold doesn't have the meaty section. Sounsd very molt like.

 

[derek_s]

He he, I'm not buying it. What about the empty shells and the decline in numbers? I know they can hide, but not forever. But, I'm no expert. I will keep my eyes open...

 

[cameron]

It can be either, but if you are seeing clones of a hermit without the meat it is probably a molt. Hermits usually tear each other up and there isn't much left other than scattered parts when they are done killing one. It could easily be a combination as well. As they molt they get bigger (often much bigger) and need bigger shells. So one could molt, need a new shell and kill a bunch trying to find it. Make sure you keep a nice variety of shell sizes in your tank for this reason.

Plus blue legs are known for killing anything meaty.