Is My Bigger Crab Bullying?

Where we discuss the behavior of our hermit crabs, as in fights, pecking orders, shell swaps, etc. Please post all naked-crab posts in the Emergency forum.
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rlegsb
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Is My Bigger Crab Bullying?

Post by rlegsb » Wed Apr 26, 2017 12:41 pm

For three years, my 3 crabs have all gotten along. The last couple of days, tho, I've found my Large crab (half dollar size shell) standing over my Medium crab (maybe Quarter size)with the tips of his legs inside Medium's shell. Medium obviously is holed up inside his shell, and there's lots of crab smack-talk noises going on. I separated them, and Large went right back after Medium. I separated them for real that time, putting Medium inside a small plastic cage I brought him/her home in, and left him (with sand, food and water) overnight. Large climbed to the top of their driftwood, while Small stayed at the top of another piece of driftwood, and they all remained that way for a day and a half. I took Medium out, and they seemed to be ok...until the next night, they were in the same position (Large holding down Medium). I separated them again, putting Large down on the opposite end of the tank from Medium. Large proceeded to take out after him/her, and Medium climbed into the water dish, across the bottom, and up the other side, and kept going, I can only imagine to get away. I separated them again. Last night, they were all loose in their 20 gal tank, with Medium sleeping on top of a plastic palm tree, while Large climbed the tallest driftwood and slept next to Small.

I am so confused about what's going on. Why all of a sudden are they not getting along? What should I do? Also, should I get more - would that temper the bullying, if that's what it is? Please help. I have found such great advice from this site, that I have immensely enjoyed the change in my crabs from no activity when I first brought them home, to continuous activity every day. Thank you in advance for any advice you may have! :)

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Hermias_mom
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Re: Is My Bigger Crab Bullying?

Post by Hermias_mom » Wed Apr 26, 2017 1:45 pm

If I saw the behavior you describe, I'd think Large was trying to either take Medium's shell or eat Medium. So I'd make sure you have 5+ shells of the right size and type - you can never have too many shells. :) I'd go buy more shells, personally, that Large might like, maybe that were lighter, both a bit smaller and larger than Large's current shell. Maybe make sure they have a soft/pearled interior if you can. I can't tell what kind of crabs you have, but the preferred shell guide is here http://www.hermitcrabassociation.com/ph ... 24&t=92552 and there's also some recommended vendors/shopping resources on the Forum if you look.

If the size difference is enough that you don't think Large is going after Medium's shell, I'd suspect nutrition. Maybe take a look at what you are feeding and try to expand your selection, especially types of protein and calcium, maybe offer some boiled shrimp or (other type of) crab exoskeleton and meat, and see if they'll eat it. Whatever you're feeding, I'd change it up, and see if maybe several food groups and nutrient types are missing from what you typically offer them to eat. Food pyramid and safe food guides are here: http://www.hermitcrabassociation.com/ph ... m.php?f=25 Also, Hermit Crab Patch sells a mineral supplement several longtime crabbers feed their crew.

Or it might just be normal crab behavior that you're seeing. Hard to tell without pictures.

I'm pretty new to crabbing myself, but I've been reading the forum a lot - these are the things I'd try. Best of luck!!!
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GotButterflies
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Re: Is My Bigger Crab Bullying?

Post by GotButterflies » Wed Apr 26, 2017 3:18 pm

Sounds like trying to a possible shell jack to me- how many shells do you have? The HCA recommends 3-5 shells per crab available at all times, but I always recommend more. There are incorrect shells to buy. (Ones hermits don't particularly care for). Please refer to the shell guide for those.

If that isn't the case I wonder about the sex of the crabs- perhaps that has something to do with it.

Remember to dip the medium crab in the fw of the crabitat before reintroducing him/her back into the crabitat. Good luck!


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rlegsb
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Re: Is My Bigger Crab Bullying?

Post by rlegsb » Wed Apr 26, 2017 4:00 pm

I will put additional shells in the tank when I get home. I have several extra in the tank, but I'll add a few more, too. I also bought a couple more crabs, hoping maybe that will give them all something new to do, instead of push their weight around the tank. These are already active, as they are crawling around a container on my work desk. :D I will also try new foods to shake things up a bit. Thank you for all your help!!

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HeyItsEggs
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Re: Is My Bigger Crab Bullying?

Post by HeyItsEggs » Wed Apr 26, 2017 4:17 pm

rlegsb wrote:I will put additional shells in the tank when I get home. I have several extra in the tank, but I'll add a few more, too. I also bought a couple more crabs, hoping maybe that will give them all something new to do, instead of push their weight around the tank. These are already active, as they are crawling around a container on my work desk. :D I will also try new foods to shake things up a bit. Thank you for all your help!!
You say you have a 20 gallon? The max amount of crabs in a 20 is 4. You are now over crowded, which could lead to cannibalism, fights, stress and more. Depending on how many crabs you have. Medium crabs and under need 5 gallons per crab, large need seven and jumbos need 15. To find out the size, use the sizing chart, I am not sure where to find that so hopefully someone else can send you the link! :D :D
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Four PPs, Rio, Rolo, Curlz and Malibu in a 40 gallon
May they rest in peace- Mango- 1/13/17 and Stefanio- 1/10/17


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rlegsb
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Re: Is My Bigger Crab Bullying?

Post by rlegsb » Wed Apr 26, 2017 4:28 pm

I've read the rule of thumb is 1 crab per gallon, so I should be able to fit 15 - 20 small to med crabs... I've also read measure the size of their shells, allowing one inch per gallon. I would think a 20 gallon tank should be plenty of room for 1 Large crab (half dollar size), 1 medium crab (quarter size), and 3 small crabs.

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HeyItsEggs
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Re: Is My Bigger Crab Bullying?

Post by HeyItsEggs » Wed Apr 26, 2017 5:24 pm

No, the rule of thumb is 5 gallons per crab.
Sophia aka "Eggs"
Four PPs, Rio, Rolo, Curlz and Malibu in a 40 gallon
May they rest in peace- Mango- 1/13/17 and Stefanio- 1/10/17

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LadyJinglyJones
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Re: Is My Bigger Crab Bullying?

Post by LadyJinglyJones » Wed Apr 26, 2017 8:23 pm

I think the thumb-y rule you're thinking of is the one for small fish.

Dude, you're going to want a second tat... I'd recommend setting up a tote (like a large plastic container with lid & simple locking handles... they're a cheap option for rapid setups. 20 gal for 5 crabs, when you know you've already got an agressive larger chap seems like begging for problems.

What if they all go down at once for a moult? (It's a common-ish occurrence during some seasons)... They don't just burrow down, they build snakey tunnels all through the sub... they'll hardly be able to avoid running into each other down there.

And if a still-tunneling crab runs into an imobilized-by-the-mid-moult-state crab, the moulting crab may be cannibalized because moulting crabs put off a smell that's tasty to other crabs.

I'd try to begin the process of dividing your tribe as quickly as you can reasonably manage.

And perhaps separating bully crab from his victim by lumping him with the Littles will solve the issue. :)

Good luck!!
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RebsCritters
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Re: Is My Bigger Crab Bullying?

Post by RebsCritters » Wed Apr 26, 2017 9:48 pm

GotButterflies wrote:
If that isn't the case I wonder about the sex of the crabs- perhaps that has something to do with it.

This was my thought. It's the new moon, friends.

Can you put them back into the same tank (under supervision) and get us a picture or two (or video) of the observed "bullying"? I've read somewhere that pre-copulatory displays can look alarmingly aggressive...

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soilentgringa
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Re: Is My Bigger Crab Bullying?

Post by soilentgringa » Wed Apr 26, 2017 10:12 pm

Sometimes before a crab is getting ready to bury to molt, they can also become (I hate to anthropomorphize too much) almost sort of irritable (like when reptiles are about to shed).

It could be dominance displays, or maybe they need more protein, or more shells.

I do not think that 5 crabs in a 20 gallon is too many if you are planning on upgrading soon (if they all live through their next molts), and they have deep substrate and plenty of hides and climbing spots.

It all depends on how well your colony gets along too. Dominance displays are normal but if you ever see them actively trying to rip each other out of shells then you have an issue.

My tank is overcrowded by most standards, but these guys have all been together anywhere from 1-3 years and I've had no molt attacks or any deaths other than PPS attributed. My crabs didn't even attempt to eat their deceased compadres.

There is no hard and fast "rule of thumb" for crabbing, only recommendations and suggestions made based on what we've learned about them over the years.

1 gallon per crab is definitely not enough space unless they're micro perhaps.



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