HCA: Hermit Crab Association

Hello, everyone!

Hopefully, this isn't sending twice, because I already wrote this post but I must've clicked a wrong button or something because it didn't show up. I'm a newbie, and I have yet to get any hermit crabs. I just had a couple of questions before I went out and bought a bunch of supplies. I had hermit crabs when I was younger, but my parents did most of the care.

1. Is saltwater necessary for all types of hermit crabs? What does it provide them? I only remember having freshwater in my habitat from years ago, but it could have been that the information was outdated.

2. I was planning to set up a little freshwater waterfall for them. As long as there are pebbles along the floor of the tank to keep them from drowning, is that alright?

3. Stepping out of routine is not easy for me, so the dietary needs concerns me. If I just have a balanced menu rotating every three days or so, will the crabs get bored or be vitamin deficient or anything?

4. My tank is 10 gallons. Will three Ecuadorians or Purples fit in there okay?

Thanks for your help!

Hi and welcome to HCA. I highly recommend reading the care guides linked here:

viewtopic.php?f=51&t=92457

To answer your questions:

1. Yes. They absolutely must have both fresh and marine grade saltwater (mixed from a product like Instant Ocean-not "aquarium salt".) Both waters need to be treated to remove heavy metals, chlorine and ammonia. Tap treated with Seachem Prime or another approved product listed in the care guide is the most cost effective and best for the crabs. They are from the shorelines and there are over 70 elements in the ocean water that they need to thrive and molt successfully.

2. This is really not recommended as the risk of flooding is super high and the crabs need at least 6" or 3X deeper than the largest crab's shell of substrate. Sand being dragged in to the waterfall will also gunk up the tubing/filter. Playsand mixed with coconut fiber is what we suggest at HCA. Land hermit crabs will not drown in water unless they cannot climb out. They need water dishes deep enough to submerge in.

3. Hermit crabs can be fed a variety of foods, and the Safe list is linked in the care guide. They need decaying leaf/vegetable matter, protein and calcium/chitin sources as well as fruit, nuts, grains, etc. It is very cheap and easy to feed them from bits of food used in prepping your own meals.

4. No. Ecuadorians need deep sub and plenty of space. It is my personal opinion that they need a larger tank than PP's and aren't as tolerant of crowding as PP's. E's are known for aggression and cannibalism in too small crabitats or with too little protein in their diets. Not all E's, but enough that it's a known "thing". They are also like the digginest crabs.
There is a tank size guide linked in the care files as well. For 3 medium PP's, a 20 gallon tank would be fine, just remember that they grow quickly in good conditions.




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Thanks so much for answering my questions. I'll definitely adjust. I really had my heart set on some moving water feature, though; if I sectioned that part of the tank off from the deeper substrate, would it work? I understand if it doesn't, just trying to work with it as much as possible.

They need the entire footprint of the tank really, for adequate substrate. You can look in the DIY section and see if it has been done in the past, but if I recall correctly, for the people who had done it, the negative aspects of the gunk in the system and flood potential far outweighed the coolness factor of having the waterfall.

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I appreciate you being so prompt. I'll look under DIY, but I can see what you mean and I'll likely have to nix it.

They drag so much stuff into the water that it will destroy the motor within a few months, even with foam and filters in place to try to prevent it. They trashed my fountain in two months. :crybaby:

I'm sorry to hear that, Wodesorel. I think I'll just put a few live plants to get the vibrant, spry sort of vibe I was hoping for.