HCA: Hermit Crab Association

Hi! I'm brand new to the forum and have had my first pair of PPs for about 2 weeks now. I want to provide them with appropriate shells in their tank but am unsure of what sizes I should put in the tank for them to peruse. Right now they're in the shells they had at the pet store which have openings of about 1.5cm. For 2 PPs with shell openings of that size, how many shells would you recommend and of what variation of sizes? I'd like to order some soon from http://deltonaseashells.com/home but don't want to waste my time or money on shells they don't need.

Thank you!

They sound tiny! Crabs that small grow quickly.

The more shells, the better. However, I'd say a minimum of 10 so it's 5 for each of them in graduating sizes. I wouldn't go any smaller than what you have now but you should get a few in 1/2 inch in case they hate their current shells and esp if they're painted. Then I would get a few more in 5/8ths and 3/4ths. It's up to you though. If you take care of them well and there's no freak accidents, they'll always eventually need bigger shells so, if you end up with shells that are too big, they're just investments for the future.

But, I'd also say there's always going to be an element of waste, at least in my existence so far. Just as an example, I have 5 jade turbo shells in my tank for my jumbos but there's one that even my frequent shell changing diva crab won't try on. I can't tell what's wrong with it but, apparently, it doesn't hold up to their scrutiny. It's in that regard, there will be some wasteful shell purchases but there's no way to anticipate that.

Thank you karlys! That's very helpful, I appreciate your time! I completely understand what you're saying about unavoidable waste, I just wanted to minimize it as much as possible and give my PPs what they need. Is measuring the opening of a shell the standard way to measure a shell for hermit crabs?

You're welcome.

Yep, measuring the shell opening is the best way. Basically, it needs to be big enough to let them retract into the shell and fit all their limbs. Although, sometimes they'll pick shells that are too small or too big. It's far far far away from an exact science lol. They're nonsensical crazy weird but amazing and fascinating creatures.

I had the same question. I have a bunch of turbos in my tank that look like they're slightly larger than what my two PPs have now. (They're both in painted shells.) They have looked at some of the shells and Harvey switched for an hour or so but then switched back. He did pick one that looked too big for him.

When I measure what size they are now so I know what size to get that will be slightly larger, do I measure the opening of the current shell they have now? Or the space their legs take up when curled in?

Also, how do you guys offer your shells? I have some in a bowl and I will put ones that I think are good size on the substrate next to where the intended crab is hanging out.

From just a month of personal observation I have four PP and it seems different crab to crab. There's no telling what they will actually go for. So just give a good variety of everything. When I started all the shells were in one place on the ground then I added more shells for variety. the extra shells I tucked in other places like the upper lvl moss pit. you could even try in the water pools if they swim? Jeffy shopped for a long time. Hed Try one on but go back to his original shell. But when I put more variety up into the moss pit he made a permanent change into a green Turbo. (Permanent so far) whatever makes them comfortable enough to seal the deal on that new home.
Crabs are scavengers let them scavenge

Hello A lot of us set up shell shops We use plastic baskets lined with coco fiber matting, or shower caddies, and fill them with clean shells. Having them in a second floor of the crabitat helps keep them a little cleaner

As far as size...I always keep shells of all sizes available. I go around the same size, and then up from there. Each crab is different as to how they like their shells. I have some crabs that go into smaller shells for molting, and some that prefer larger shells for molting.

Here is the shell guide: viewtopic.php?f=24&t=92552

GotButterflies wrote:Hello A lot of us set up shell shops We use plastic baskets lined with coco fiber matting, or shower caddies, and fill them with clean shells. Having them in a second floor of the crabitat helps keep them a little cleaner

As far as size...I always keep shells of all sizes available. I go around the same size, and then up from there. Each crab is different as to how they like their shells. I have some crabs that go into smaller shells for molting, and some that prefer larger shells for molting.

Here is the shell guide: viewtopic.php?f=24&t=92552

Thank you! I have definitely checked that out as well. I did made a lower bowl and a higher shell shop but it took them a while to get up there - one of them just figured it out last night and did some shopping up there so I felt better about their access to the shells after that!

Tat by Jesse O., on Flickr

Glad you feel better about it. Don't be afraid to try different stuff you may discover something about your crabs.