HCA: Hermit Crab Association

I have a 55 gallon, and I recently wanted to get a topper for them, only because I thought it’d be a good addition for them to use, and enjoy. My parents aren’t sure about the idea, and I don’t know if I’ll be able to get it.

I wanted to know how long my crabs will last in my tank, according to their sizes.
I have seven hermit crabs, and they vary in size. Here’s a good approximation on their size and behavior.

Crab #1 - Borderline Jumbo
Crab #2 - Borderline Jumbo
Crab #3 - Large
Crab #4 - Medium
Crab #5 - Medium
Crab #6 - Small
Crab #7 - Small

I think I got the right sizes, I lose track on their sizes.


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I edited your title...

That is really hard to say. We really recommend jumbos to have at least 75 gallons. Every crab grows at a different rate.

Edit: Just remember though, you are fortunate enough that your parents have allowed you a large tank to begin with. Some don't let their kids get animals period. Make sure you express gratitude for what they have allowed you to have while you are living under their roof

GotButterflies wrote:I edited your title...

That is really hard to say. We really recommend jumbos to have at least 75 gallons. Every crab grows at a different rate.

Edit: Just remember though, you are fortunate enough that your parents have allowed you a large tank to begin with. Some don't let their kids get animals period. Make sure you express gratitude for what they have allowed you to have while you are living under their roof

Okay, thanks.
It appears that everyone has room to themselves, no bumping into each other.
I cannot upgrade while I live here with my parents, so I must have my own space to do further projects.

I think I will stick to what I currently have, and go from there. I will be installing new pools this fall, so that'll surely clear up some more room.
I'll also try to get a photo of my largest crab on the scale.

The HCA does recommend a 75 gal for jumbos, but PPs can tolerate more crowded conditions.

Just make sure they have deep substrate and lots of hiding places, and you can make do with a 55 for a few more years.

JoeHermits wrote:The HCA does recommend a 75 gal for jumbos, but PPs can tolerate more crowded conditions.

Just make sure they have deep substrate and lots of hiding places, and you can make do with a 55 for a few more years.

Okay! Thanks, that'll be just fine.
I will hold off on the topper until my parents approve of it.
When I make changes, I am increases my substrate depth, and remove my caddies.

JoeHermits wrote:The HCA does recommend a 75 gal for jumbos, but PPs can tolerate more crowded conditions.

Just make sure they have deep substrate and lots of hiding places, and you can make do with a 55 for a few more years.

Well within a few years a large can become a jumbo, and considering that there are multiple borderline jumbos, hey can become jumbos quite quickly. I would assume that they would last roughly a year

AwesomeHermit wrote:

JoeHermits wrote:The HCA does recommend a 75 gal for jumbos, but PPs can tolerate more crowded conditions.

Just make sure they have deep substrate and lots of hiding places, and you can make do with a 55 for a few more years.

Well within a few years a large can become a jumbo, and considering that there are multiple borderline jumbos, hey can become jumbos quite quickly. I would assume that they would last roughly a year

That’s true. We just need to make sure they don’t feel overcrowded.

Lots of hiding spaces are appreciated, but from my experience you will seldom have all crabs up at the same time (some will be underground). This will also cut down on overcrowding.

Stella wrote:

JoeHermits wrote:The HCA does recommend a 75 gal for jumbos, but PPs can tolerate more crowded conditions.

Just make sure they have deep substrate and lots of hiding places, and you can make do with a 55 for a few more years.

Okay! Thanks, that'll be just fine.
I will hold off on the topper until my parents approve of it.
When I make changes, I am increases my substrate depth, and remove my caddies.

How deep is your substrate now? Jumbos prefer 12” or greater. However, they also need climbing space. If your substrate’s already twelve inches deep you may not need, or want, to add too much more.

JoeHermits wrote:

Stella wrote:

JoeHermits wrote:The HCA does recommend a 75 gal for jumbos, but PPs can tolerate more crowded conditions.

Just make sure they have deep substrate and lots of hiding places, and you can make do with a 55 for a few more years.

Okay! Thanks, that'll be just fine.
I will hold off on the topper until my parents approve of it.
When I make changes, I am increases my substrate depth, and remove my caddies.

How deep is your substrate now? Jumbos prefer 12” or greater. However, they also need climbing space. If your substrate’s already twelve inches deep you may not need, or want, to add too much more.

It’s currently eleven inches deep.


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JoeHermits wrote:

AwesomeHermit wrote:

JoeHermits wrote:The HCA does recommend a 75 gal for jumbos, but PPs can tolerate more crowded conditions.

Just make sure they have deep substrate and lots of hiding places, and you can make do with a 55 for a few more years.

Well within a few years a large can become a jumbo, and considering that there are multiple borderline jumbos, they can become jumbos quite quickly. I would assume that they would last roughly a year

That’s true. We just need to make sure they don’t feel overcrowded.

Lots of hiding spaces are appreciated, but from my experience you will seldom have all crabs up at the same time (some will be underground). This will also cut down on overcrowding.

Sorry that this conversation sounds like an argument, but sometimes I have all four crabs up in my 20-gallon tank, which can be somewhat crowded, even though my crabs are smallish. You would want to consider what would happen if all of your crabs are up, for a worst-case-scenario. Good point on crabs being underground though.

I also wanted to mention that this crab I am speaking of is extremely active. He can be in one spot when I peek at him, and quickly across from that in just ten seconds or less.

There isn’t one inch he hasn’t climbed or explored.


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AwesomeHermit wrote:

JoeHermits wrote:

AwesomeHermit wrote: Well within a few years a large can become a jumbo, and considering that there are multiple borderline jumbos, they can become jumbos quite quickly. I would assume that they would last roughly a year

That’s true. We just need to make sure they don’t feel overcrowded.

Lots of hiding spaces are appreciated, but from my experience you will seldom have all crabs up at the same time (some will be underground). This will also cut down on overcrowding.

Sorry that this conversation sounds like an argument, but sometimes I have all four crabs up in my 20-gallon tank, which can be somewhat crowded, even though my crabs are smallish. You would want to consider what would happen if all of your crabs are up, for a worst-case-scenario. Good point on crabs being underground though.

No, not at all! It’s good to have different perspectives, and you’re right, a worst-case scenario should still be considered.