Territorial behaviour and shell fights

[Wai]

I recently adopted three hermit crabs (Europa, Io and Callisto) from someone who couldn't look after them anymore. I intended to isolate these three for a week or so, but I decided to give all of my hermit crabs a quick bath together to see how they would interact. I placed them inside a container to dry and I didn't detect any suspicious behaviour. I guess they were all focusing on finding a way out of the container.

Once I put all the crabs in the main tank after the bath to see how things would be like, the tables turned. Vesta was much larger than Europa and certainly couldn't fit in the latter's shell, but he grabbed on and began jabbing at Europa's body. Later when I pulled him off, Vesta chased after Io, who was of similar sized and was clearly after the latter's shell. Vesta chased after Io twice. More scarily though was Flora, who was half Callisto's size, charged at the latter head on for no apparent reason. Callisto ran away backwards in fright.

The three newcomers are now isolated for the time being. I have never seen such aggression to newcomers, in particular all three of them at the same time. Has anyone else had such behaviour happen? Not even the bath helped.

[aussieJJDude]

What have you done so far, separated the aggressor? I would suggest keeping him in ISO for a while, providing him food, water and some new spare shells for him to calm down.
Maybe rearrange the tank as well, so the newcomers have a chance of settling in the the new surroundings and let them get all the "pheromones" all over the place for a couple of weeks and then re-introduce the aggressor - so vesta/flora are the newbies?

But it sounds like your crabs where just displaying their dominance towards the newcomers and letting them know who is boss. However, it does sound like vesta is interested in io's shell. I'd suggest purchasing some similar to io's and seeing if it can distract him a lot more.

[Wai]

Callisto, Io and Europa are the three newbies and they have been timid thus far. As they were being targeted, I isolated those three and left the old crabs in the main tank. Today I reintroduced them again and the old crabs started being unpleasant to them; however, I was watching the whole time and no-one was hurt. The old crabs have stopped bothering the newbies. I guess they were interested in the newbies' shells, but gave up trying to steal them. I will continue to observe their behaviour today (as I have the day off) and if there are any problems, I will isolate them again. I would rather have the fights occur when I am able to supervise and intervene if there are issues.

[ladybug15057]

I've read of this happening in the past Wai. Sad, but true. It sounds as though even though another had these hermies they were not provided for with their needs being met and so much aggressive behavior being showed. I too would keep them separated until most of the aggressive behavior was gone. Maybe next time after their bath put some freshly boiled shells and a bit of food in the drying area? Do you have a container they can all fit in during their bath so they could smell the same? And as suggested, prior to putting them all in the same tank eventually move some items around. Usually a hermie has their favorite spot for relaxing and take away one other possible aggressive moment in the tank?

[Wai]

Sorry about the late reply; I just got back from overseas a few days ago. All of my hermit crabs were okay in my absence.

Before I left, the hermit crabs had a bath together and were placed in the same container. I think they were too occupied trying to look for an escape route and did not bother each other. However, once I put them in the main tank to test their behaviour, the old crabs started harassing the newbies.

For now, the hermit crabs appear to be fine and there is no more aggression.

[ladybug15057]

Welcome back! Happy to hear the little ones are starting to behave themselves. Some do say that if they rearrange their tanks too this helps. Some hermies have that favorite spot and will defend it too. Whether it is the spot, or a piece of decoration.

[charcoal44]

I had originally posted the below on 27 Jan, under "Good Substrate" in the Care Forum, I think what happened with my crabs is similar.

27Jan.
Well, my original lost a limb today, I believe as a result of a domestic dispute.
He's been in a little half coconut, and the big one was in there this morning, when I took him out I found the limb.

I'll check on him over the next couple of days, he's been kind of quiet for a while now, not moving around at all, and I've not seen him in either the fresh water or salt water pools. And he's not been near the food dish.

28Jan.
Bad news, well terrible news.

Checked on him this morning to find his dismembered limbs inside the coconut shell, and his shell upside down.
It goes without saying there was no point in trying to do anything for him by this stage.

I'd had him from the start last April, he was the last of the original 3 I got.

This cant have been a case of the big one wanting the little ones shell, it was too small for him, and he'd already moved into a bigger shell.

What causes this behavior?