HCA: Hermit Crab Association

I've seen a few members mention "modified shells" with the modifications being something that the crabs themselves do. I'm very confused. Can someone kindly explain what exactly these modifications are? Why do the crabs do them? Is an unmodified shell just as good or will crabs automatically reject them?

It's a good deal of questions, but I appreciate any answers.

Crabs will pick and chip at a shell with their claws, they might make a dent for their eyes or some body part, and Es tend to 'gut out' the shell (remove the spiral) although why and how is not really known.
Crabs actually prefer hand me downs, if it smells like another crab, or they see another crab wearing it, it must be good, right? They're just fine, although the gutted out shells will probably only be popular with Es.

Ohh, okay. That actually makes sense now with the shells my e's are in. I've got two of them in whales eye shells and they've got bits missing in the front just above their eyes, and when merry died I noticed his shell looked strange in the inside.

I've been told e's are super picky about theory shells and don't anticipate mind moving at any point in the immediate future, but do you know anywhere I could likely get "hand me downs" for cheap? I've got a couple extra shells in the tank but two are dully unmodified and the third is merrys old shell which is the tiniest out of any shell (including the ones my crabs are wearing)

Well, you could buy/trade shells with a nearby crabber, or usually pet stores will let you buy the empty shells in the tank with the crabs, but these are often painted or inappropriate for crabs.
I usually get my hand me downs from newbies, I give fresh shells to a newbie on the way home or during quarentine, then I have his empty shell to offer to mine, and when he moves into the main tank he usually changes again, and everyone goes nuts for his shell, leaving THEIR shell empty, and someone wants that one. This cycle can go on and on and on, leaving almost every shell worn once or twice, so it's now a 'used' shell
The jumbo I just adopted was in a way too small shell, so he changed four times before choosing a bigger one! So I now have his old shell, and all the one's he tried on but didn't keep that will smell 'used' to my jumbos that are underground molting
In the wild, when a large crab finds a new empty shell, a smaller crab will wait beside him, and a smaller one will wait behind him, so they all get the hand me down thats a bit bigger then theirs, they can have huge 'shell swap chains' sometimes, the big guy changes, and the smaller guy takes his old shell, and so on.
Hope that helped

Very much, thanks!

E's modify their shells so that they can stay in them longer, and also decrease the weight as they increase the volume of the shell. This means more energy can go to growing instead of carrying around a heavy shell. Where E's are, shell competition is a pretty serious business, so being able to stay in your shell as long as possible is a huge advantage. That's why they modify.

Some people don't like to offer the modified shells when the E's change out of them because of the sharp edges. Others figure that if the E's had them in nature, it won't matter if they have them in captivity.

Correction, why is not really known to me thanks!

These are some examples of what the inside of an Es shell looks like. The longer they wear them, the more they turn into an empty cap! I've had them come from the store wearing shells where they were nothing but a beanie over their rears. Normally they'll change before the shells get really bad, but if they're comfortable they will stay for years.





I've found that my Es have been extremely willing to change shells in captivity. I've had lots of luck with babylonia, bai, Mexican (fluctosus) turbos, small pletho turbos, and starry orange nauticas (hard to find!). My largest is currently in a tonna shell. Lightweight seems to be secret, and they will start modifying them within a few months of wear!

Premodded nerites and zebra littorinas are going to be a huge hit IF you can find them and IF you have the right sized crabs. I lucked out when I got my original baby Es and found shells a little larger than what they were wearing in a pet shop already modified. Within five minutes there was an insane changing party and not one of the five stayed in their original shell.

^ the second one was what merry's looked like.
it surprised me, only because i figured they wouldn't be able to grip it as well.

Have you ever seen the rear end of an E? They're crammed so tight into those shells I'm surprised they can get out of them!

sadly, when merry switched he did so on valentine's day (during the day though. it was funny, my boyfriend and i were watching a movie so i turned off the lights and shut the blinds so i guess he figured it was dark enough to do his thing. when we turned the lights on he'd made the change. when he switched back a few days later it was during the middle of the night) so i've never seen an e's butt.

Anorable wrote:sadly, when merry switched he did so on valentine's day (during the day though. it was funny, my boyfriend and i were watching a movie so i turned off the lights and shut the blinds so i guess he figured it was dark enough to do his thing. when we turned the lights on he'd made the change. when he switched back a few days later it was during the middle of the night) so i've never seen an e's butt.

Lol Merry switched on my bday!!! I have some Es so now i know wut to expect as they are new to my family

Aah... Thanks, everyone who posted here. I heard crabbers mention modified shells, but I had no idea what they meant!