Aggression: introducing new crabs

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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seatmon
Posts: 2
Joined: Thu Apr 11, 2013 7:02 pm

Aggression: introducing new crabs

Post by seatmon » Tue Oct 28, 2014 3:07 pm

Hello all,

We have had hermit crabs for 10 years, but we have never introduced new crabs into our mix. My son got 2 crabs for his 6th bday from a relative, in one of those little plastic crab cages w/ a food shell and a sponge :shock: We quickly researched them and built a nice 50 gallon tank for them. Within a week one went down to molt and we thought the other would be lonely and bought 3 more friends. (So I guess we have introduced, but they were all pretty much new, and we had no problems).

Last year we had one die right after molting (dug between the water bowl and the glass and got stuck, I think because she was still weak from molting, I didn't find her in time to free her). Two months ago our largest (and my son's favorite) Elma Fudd was came up from a molt naked, leaving her shell behind in the hole. We think her tunnel must have been collapsed from another crab digging nearby and she came up for air, too weak to bring her shell. We isolated her and got her to re-shell, but she died a few weeks later.

Because we are now down to 3, we bought 3 more hermies to introduce. We got the largest we could find, but they are still very small compared to our 10 year old crabs! Our 3 big ones are larger than golf ball sized, the new ones are quarter sized and smaller. We tried to introduce after a week in iso and the bigger crabs seemed aggressive so we separated again. I waited until everyone had decompressed and tried again today (about a month later) bathing and introducing one big and one little who were up and about (and had been for a few days) in the big tank. The little stayed hidden, the big went straight over to investigate, climbed on top of little's shell and was hanging on. I let that go for a little while but then all of a sudden biggie quickly flips over little's shell and starts trying to grab inside. I separated and put little back in iso tank (biggie DID NOT want to let go, and is still very active/agitated walking and crawling all over tank).

Suggestions? Is it possible to introduce? What should I try?

Thanks!!

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CallaLily
Posts: 3831
Joined: Sun Aug 03, 2008 9:05 pm

Re: Aggression: introducing new crabs

Post by CallaLily » Tue Oct 28, 2014 3:29 pm

A quick dip in the freshwater pool before introductions can help. There will be some dominance displays just keep a close eye on things for a while. Antennae "fights", flicking/shoving, and standing over another crab. Maybe some claw waving or raised limbs. It's usually worked out fairly quickly with no injuries. I know it can be tough to watch but, unless a crab is pinching causing injury or trying to steal a shell, it's ok to let it play out. If it gets too out of hand, another dunk in the freshwater and opposite ends of the tank. Just keep watch for a while. Good luck!


Topic author
seatmon
Posts: 2
Joined: Thu Apr 11, 2013 7:02 pm

Re: Aggression: introducing new crabs

Post by seatmon » Tue Oct 28, 2014 3:38 pm

What about shell flipping? Is that aggression or just curiosity? Both times i tried to introduce the big one would flip the little one over and get on top. It looked like he was trying to get into the shell/pull the other out, but I didn't let it get that far. The little one was just staying tightly in shell...

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CallaLily
Posts: 3831
Joined: Sun Aug 03, 2008 9:05 pm

Re: Aggression: introducing new crabs

Post by CallaLily » Tue Oct 28, 2014 3:40 pm

Definitely seperate if it looks like he's trying to pull another crab out of it's shell. But if he's just flipping and standing over the crab, just keep a close eye.

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