HCA: Hermit Crab Association

Hi! Okay, so I've never had crabs before but I do have other exotics (mostly tarantulas) and I really want to get a couple crabs too!
I read the basic care sheets and some of the other ones about like water and food and substrate and stuff, but I want to make sure I'm super ready before I get the crabs so they can have a really happy home! I was hoping someone could look at my plan and tell me what needs to be changed before I put any crabs in it and maybe stress them out or hurt them...

So I'm planning to get 2 small crabs and want to start them off in a 20gal & put a UTH on the side (with a hygrometer/thermometer too), although I think once they grow they'll maybe need to be sized up...I've read 5 gal per crab so I'm thinking with 20 they'll get 10 gal apiece and that will be a good starting point while I look for a cheaper bigger tank if needed? The lid is screened but I'll cover it partly with saran wrap to hold in the warmth & moisture.

I have a lot of coco fibre on hand so I'm planning on doing the 5 parts sakrete play sand to 1 part coco fibre that I've read on here. The aquarium salt I'm getting is the Instant Ocean sea salt for the salt water. I have the tap water conditioner from Aqueon for dechlorinating.

I'm planning to get the following foods (I know that fresh is better for the proteins but I'm a vegetarian and I don't think I can stomach having like seafood in my fridge...): Hikari Bio-Pure freeze dried bloodworms, Fluker's freeze dried grasshoppers, nori sheets, zoo med freeze dried fruit salad (in case I don't have enough fruits & veg on hand), eggshells, roasted unsalted sunflower seeds (for the fats--although I'm not 100% sure this is the right way to get them fats...), & I also almost always do have a lot of like zucchini, peaches, apples and the like too.

I have a couple more specific questions:
Is there a best place to like..."ethically" get hermit crabs or is it ok to buy them at a local pet store? I'm worried about having them shipped if bought online because it's so hot here right now.
How much food per crab is appropriate? Like, do I give them one half of one slice of my apple or a whole slice or a whole apple?? How many worms? Is there a general rule like "provide an amount of food equivalent to the size of the crab" etc.
If I supplement with reptile calcium, should it be with D3 or without? Or it doesn't matter?
Should I dust all their food with said calcium or just some of it?
How do you deliver fats to them if you were to use like, coconut oil or something? Do you just put a dollop in there or put it on their other foods?
I know you shouldn't have any decor they can chip or scratch off, but plastic plants are OK? I'm worried they'll clip off pieces of plastic plants, but I want them to have enough cover...

Sorry for all the info dump, I just want to make sure I'm all set up & the crabs are ok when I do bring them home! If you have other advice please let me know since I'm a total newbie to crabs!

Thank you guys in advance!!

Hi! Okay so there are a few things on there I’m not sure of but I’ll answer what I can.

1. Ethically, try to adopt on Craigslist or Facebook or just look around and see if you can find some that need homes rather than buy them from pet shops. It helps not support the pet trade since they are all wild caught. You can apply to adopt new babies as well with the land hermit crab owners society! I plan to do that in the Future to support captive breeding
2. As for the food I read somewhere that about a tablespoon per crabs worth of food is about right.
3. I would recommend looking for food on Etsy. Worm castings, green sand, and foraging mix would help out alot! And they have a bunch of seafood options that you wouldn’t have to see in the fridge.
4. Tank size. They mostly recommend a minimum of 10 gallons per Crab. So if you have the ability to get a bigger tank I would recommend it. I’m about to be driving so I’ll reply again when get home


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Okay I’m back!

So. Back to the tank thing. 20 gallons is fine for two crabs that are smaller. From personal experience I recommend starting off bigger because I’ve done three tank upgrades in two months and it’s so exhausting and expensive lol.

5. Instant ocean is perfect. For the de chlorination I don’t know that brand I just know you have to have something that gets rid of the chlorine, heavy metals, and ammonia I think.
6. The reptile calcium I have NO clue. I’ll need someone else to confirm on that one.
7. For fats like oils or honey or stuff like that I get a smaller food bowl or like I’ll put it in a sea shell tipped over inside their food bowl but I think you can mix things and it won’t matter.
8. So make sure for decor you check wood. Apparently that’s one of the worst things ever because most of the wood things made for pets are out of unsafe wood for them, example: pine. So double check that. And as far as I know the plants thing, just watch them and monitor if they are clipping at them or destroying them. I have fake plants and mine are just fine.

As for advice. I would look up the Post Purchase stress method from Crab central station on YouTube and watch their videos. They are VERY helpful and will help you a lot! Hope this helps!


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Thank you!! do you think a 30 gallon would be enough or is it really best to just go 40? If 40 would be best I might just wait until petco has their next dollar per gallon sale lol.

I will definitely check out that video! thank you!

I would just wait to get a 40 if you already have a 20 already. If you don’t already have a set up, anything 20 and above is enough! and you’re welcome! If you have anymore questions let me know!


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Please don't watch videos or research the method mentioned. It has not been proven to increase survival rates, and is based on theory that does not apply to crabs. HCA does not recommend that method - it is better to get crabs into ideal conditions as soon as possible!

Also, pine is not unsafe if it has been dried- which is what all decor sold in pet stores has been. Only the fumes (phenols) from fresh pine could be problematic in a closed in space like a crab tank.

Is there a best place to like..."ethically" get hermit crabs or is it ok to buy them at a local pet store? I'm worried about having them shipped if bought online because it's so hot here right now.
Curly - HCA has an adoption forum, organized by location, you can look to see if anyone is re-homing crabs in your area, or post that you are looking for crabs too!
viewforum.php?f=13
How much food per crab is appropriate? Like, do I give them one half of one slice of my apple or a whole slice or a whole apple?? How many worms? Is there a general rule like "provide an amount of food equivalent to the size of the crab" etc.
Curly - I have two crabs, that I have had for over ten years. I usually put about 1/4 to 1/2 tsp of four or five different dried foods into a shallow flat dish. If I am feeding fresh, I will put about a teaspoon each of four or five different foods. Then I have a dish of leaf litter (either fresh or dried leaves from my yard), and always have a chunk of cuttle bone in the tank. When crabs are small, the number one question is whether they are eating because they eat such small amounts. I swear that for the first few years, I put in and took out the exactly same amount of food! The only way I knew they were eating is because they were alive.
If I supplement with reptile calcium, should it be with D3 or without? Or it doesn't matter?
Should I dust all their food with said calcium or just some of it?
Curly - I have never fed reptile calcium, I have only ever fed egg shells, cuttle bone, and a 'calcium mix' that I bought from Hermit Crab Patch.
How do you deliver fats to them if you were to use like, coconut oil or something? Do you just put a dollop in there or put it on their other foods?
Curly - You can use very small bowls, or even something like a bottle cap. If you are feeding a liquid or something that could get goopy in the sub, consider putting the small bowl into another container like a flat square Rubber maid food container, just to contain the mess.
I know you shouldn't have any decor they can chip or scratch off, but plastic plants are OK? I'm worried they'll clip off pieces of plastic plants, but I want them to have enough cover...
Curly - Most of us use fake plants. Mine have shredded pretty much any I have put in, I currently don't have any because of that LOL. I have a reptile hide, and a cheap dollar store container that I flipped over and cut a 'door' in for them to hide.

Be sure to check out the care sheets. There are ones all about how many crabs in what size of tank. I had my two in a ten gallon for the first couple of years, then traded it for a twenty gallon for two or three years...then lucked into a free 55 gallon! I'm glad I didn't pay a bunch of money fora huge tank at the start.

Here is the care sheet that tells you which types of dechlorinator remove what:
viewtopic.php?f=127&t=92553

Here is the care sheet that outlines how many crabs of what size in what size of tank:
viewtopic.php?f=26&t=92541

As a vego myself, I understand you may feel uncomfortable, but these guys require meat based proteins within their diets. While dried foods do work, they don't have the same nutritional values like fresh and a mix should be offered.

If concerned, a small Tupperware container (with a snaplock lid) could be used to store meat based products, and you certainly wouldn't need a lot and they'll be rather happy with things like small (unflavored) cocktail shrimp, seafood offcuts or beef/chicken offcuts (can even get for free from the local butcher potentially). Likewise, depending on the other animals you keep, you could double the "crab container" as an "animal container" and keep all the meats together.

I guess it doesn’t bother me to feed f/t mice or live insects…maybe it’s just because I trained my brain to see them as “animal food” instead of “people food” Maybe could f/t shrimps if they do like the seafood smell…?

Thank you for all the really good advice! I’m sure I’ll have a ton more questions as I go along