HCA: Hermit Crab Association

Hi, I posted several weeks ago about a PP crab I rescued (my friend found it wandering the streets). I've had new crabby in a tupperware and it's been doing well. It switched from its ugly too-small painted shell to a new bigger natural shell (it actually tried two before settling on the big one), and has been hogging down food & water (fresh and salt). At first I kept its enclosure covered with dish towels so it could destress but now I've been uncovering the front so it can adjust to living in the house. All it has left to do is survive a molt.

I want to put it in the 40 gal tank with my crab Calypso, but the new crab is darker colored and mottled, and I just want to make sure it isn't shell rot. I have included some photo links in different lighting, if someone can please let me know if this is indicative of shell disease or just natural color variation among crabbies. I know New Crabby will be overjoyed to be in a proper enclosure with substrate and a friend! I'd have posted this sooner but I have been dealing with my beloved pet bunny having cancer & having to be euthanized so it was all I could do just to provide basic care for sweet new crabby. Thank you!

P.S. In the photos where there's poop and mess in the background, I took the photo right before doing a daily cleaning.

https://flic.kr/p/2k4WKJE
https://flic.kr/p/2k51xAr
https://flic.kr/p/2k51y95
https://flic.kr/p/2k51ywE
https://flic.kr/p/2k4WMhj
https://flic.kr/p/2k4WMK3

It’s just a dark-colored hermit crab.


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Thank you. I'm just trying to be really careful, since I recently deep-cleaned the tank and added brand-new substrate. I did find some photos of shell rot and it looks different from what I can tell. I'll put the links below in case someone else finds this thread. I'm wondering if the crab looks darker too because it's probably had a poor diet and stressful living situation up until recently.

https://crabstreetjournal.org/blog/2012 ... ack-spots/

https://www.hermitcrabparadise.com/crab ... ellrot.php

With crabs, usually poor diet tends to wash out colour rather than the opposite. Think similar to fish (if you're familiar with them), sick fish tend to be lighter in colouration.


Shell rot is rather uncommon, and usually is coupled with deformed limbs so it can be rather straightforward to differentiate with clear view/pictures.

Ok thank you. Are my pictures good enough? I just took some more and can upload them if needed. Do you think the crab looks healthy? I do not see any limb deformation. I'm really chomping at the bit wanting to introduce the crabby to the crabitat.

aussieJJDude wrote: ↑

Mon Nov 09, 2020 9:20 pm

With crabs, usually poor diet tends to wash out colour rather than the opposite. Think similar to fish (if you're familiar with them), sick fish tend to be lighter in colouration.


Shell rot is rather uncommon, and usually is coupled with deformed limbs so it can be rather straightforward to differentiate with clear view/pictures.

Kitkat7 wrote: ↑

Mon Nov 09, 2020 9:35 pm

Ok thank you. Are my pictures good enough? I just took some more and can upload them if needed. Do you think the crab looks healthy? I do not see any limb deformation. I'm really chomping at the bit wanting to introduce the crabby to the crabitat.

Ah woops. Forgot to say, yeah. Healthy crab (agree with Joe!).

My bad.

No problem! Thanks again.

aussieJJDude wrote: ↑

Mon Nov 09, 2020 9:41 pm

Ah woops. Forgot to say, yeah. Healthy crab (agree with Joe!).

My bad.

Well, thanks again for the feedback. Since it's getting late I'm going to wait and introduce the new crabby to the tank tomorrow morning, so I can keep an eye on them as they get acquainted. I hope it will go well! *fingers crossed*

Hope all goes well!

Good luck...keep us posted!


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I just wanted to add that your crabby looks good to me, my two larger crabs are kinda similar in color to yours.

Good luck with the tank move!

Update: I introduced the new crabby (now named "Frodo") to Calypso and the crabitat. They spent time having antennae and shoving battles; Calypso was actually more aggressive even though Frodo is larger. Calypso kept pushing Frodo upside down and climbing on him/her. I watched closely but didn't intervene, to let them do their thing, until I had to go out for a bit, and then I moved Frodo to the back to give him/her a break. Frodo got a slow start but then started exploring the crabitat, and eventually ended up switching shells for a third time! Poor Frodo had been stuck in a horrible ugly way-too-small painted shell; now s/he's in a pretty striped shell. Calypso and Frodo have become good buddies. Just today I came out to the living room and they were nestled up napping together in a corner. I think they're both happy to have company. Frodo has been enjoying the HCP worm casings and mineral supplements I've provided around the tank. I'm really hoping it will all help Frodo have a successful first molt in the crabitat. As of now, so far so good! Here's a few more photos:

Frodo the day I brought him/her home, making a beeline for fresh water https://flic.kr/p/2k7ioh5
This nasty painted shell was thrown in the trash! https://flic.kr/p/2k7iqxs
You can see Frodo (below) is bigger, but Calypso (top) was more dominant & assertive https://flic.kr/p/2k7etQz
Frodo in his/her third shell choice since ditching the painted one https://flic.kr/p/2k7ez8U
Frodo & Calypso napping together this morning, before & after I turned on the "sun" for the day https://flic.kr/p/2k7j7yW

The pretty striped shell is commonly called a Black Murex. Crabs don't commonly take to these, so its always nice to see one on a crab. I've been trying to get my group on to them for ages, with no luck. One day....


I absolutely love the pics, they really good quality. And I'm glad to hear that they have both settled in well!

Oh yes, I had forgotten the name. Yes it is a really beautiful shell. Calypso is in a white murex but it's stained from the old coconut fiber substrate so doesn't look as nice now. I would think the murex shells would be heavy, but whatever floats their boats! I am going to order some turbos, since my crabs liked those too in the past.

aussieJJDude wrote: ↑

Mon Nov 16, 2020 4:11 pm

The pretty striped shell is commonly called a Black Murex. Crabs don't commonly take to these, so its always nice to see one on a crab. I've been trying to get my group on to them for ages, with no luck. One day....


I absolutely love the pics, they really good quality. And I'm glad to hear that they have both settled in well!

Beautiful shells and precious hermies! Happy to hear they’re doing well...and great pics too!


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