HCA: Hermit Crab Association

I'm a long time fishkeeper whose wife and 6 year old brought a medium sized hermit crab home 2 weeks ago. Long story short my kid loves crabs and my wife dropped it and felt super bad about it. I like to keep animals alive and fortunately already had some idea of the requirements from previous consideration. After a few weeks of research (mostly here) and some purchasing + raiding my aquarium supplies I've cobbled together an attempt at a long term home for this guy:

Exo Terra 18 x 18 x 24 paludarium
Cork wood platforms and climbing wall mounted on a sheet of eggcrate fish tank divider suction cupped to the rear wall.
6-7 inch substrate (sand/coco fiber mix - partly the Flukers product).
2 larger bits of malaysian driftwood and a nice 6"cholla wood section.
The finest plastic plants that didn't seem full of dye Michaels had in stock that day.
Fresh and mixed sea water pools ~3 inches deep with air pump for circulation, undertrays, and convenient steps in/out. Still had some Coralife Aquarium Fish Tank Marine Salt, so that's what I've been using.
Ultratherm Undertank Heater 6"x11" mounted to the back tank wall with insulated back and a light dimmer switch for adjustments.
ThermoPro TP60 Digital Hygrometer with remote sensor mounted a few inches above the substrate. Stable around 77-79F @ 75-80% humidity.
Fluval Nano planted light running a daylight sim profile on a 12 hour light cycle

Plus:
3 shells around his size (he switched into one the first day these were introduced so the painted shell is gone).
Crab food from an Etsy seller who seems to mix a pretty complete set of meals.

I had to dig everything out and put plastic divider 1" under the substrate to prevent tunneling after reading through a Post Purchase Death Reduction Method article a couple days ago. Of course now I'm reading some of the controversy around the method and wondering if I should dig it back out. I'm also upgrading the UTH to the 11"x17" model next week to bump up the temperature a bit - I overestimated the heat these put out.

The crab initially was extremely inactive. He perked up a bit when I introduced him to a bare bones 7G tank with substrate/water/humidity where he, of course, immediately burrowed and only emerged at night. Fortunately he did not attempt to molt in the temporary tank while burrowed. He's been in the permanent tank for about 5 days now, still only active at night but he's definitely eating and using the pools. I like to think getting more active, so at this point just hoping he makes it!

I would not put anything to prevent molting - it is always safer for them to molt underground than on the surface. And a crab can't put off molting indefinitely, so if he needs to he will molt whether you want him to or not.
Your temp is perfect at 77-79F.
Your set up sounds awesome!
Happy crabs aren't always super active. They do spend quite a bit of time just hanging out and chilling. It sounds as tho you are doing everything you can to give him a good life! Many of us feed both dried and fresh foods. They can eat many of the same foods as we do, so you can offer scraps from your meals - grains, greens, veggies, fruits, nuts, seeds, eggs, eggshells, leaves, flowers, etc. Be sure to offer animal protein daily, as well as calcium.

Yeah I'll probably dig the divider up today or tomorrow. I originally figured it would be good for him to molt after moving into the permanent tank where I could maintain good parameters and leave him alone for a few months. I'm probably still doing the UTH upgrade because I figure when the house temp drops a few degrees during the winter I'll want the option to kick it back up to around 80.

I found him at the top of the climbing wall this morning. He pushed both his water pools away from the walls and generally rummaged around in everything so he's definitely getting more active! I've been adding a few little slices of fruit (cherries and apple) but he mostly went for the dried food mixes those nights - I figured I'd keep adding them to maintain a little variety.

Sounds good - I have always had multiple UTH's on my tanks. I live in an old farm house, with baseboard heat upstairs where the crabs are, and air conditioning that doesn't reach all the way upstairs. Canadian Prairies where it can be -40C or colder in winter and +35C or hotter in summer!
I check my tank temp at least once a day, and can plug or unplug heaters as needed LOL!

Here's my mostly complete plan for the crabitat after pulling the divider out of the sand and putting in a few more decorations to increase cover. I'm trying to make the crab feel safer by breaking lines of sight and increasing overhead cover to promote more activity.

The next step is figuring out a buddy for him by either adopting a crab or try to get a captive bred crab. I'd prefer to put money toward the hobbyists breeding them and get an already adjusted and thriving captive bred crab, wholly avoiding the wild harvest business. But it seems like that will take longer.

Well, he's been under the sand for a week and a half. No evidence of him coming to the surface at night this time, though I have heard him bump around a bit down there. Hoping he'll get through what I assume is molting.

Right on! Tank looks great!

He's still down there, since July 31st. I sometimes hear him bump the glass down there but no sign of coming up yet.

Badgerer wrote: ↑

Tue Sep 24, 2024 5:48 pm

He's still down there, since July 31st. I sometimes hear him bump the glass down there but no sign of coming up yet.

That's okay! He knows what he is doing!