HCA: Hermit Crab Association

Both my wife and I had hermit crabs when we were younger but neither of us were experts.

My wife recently 'rescued' a lone hermit crab from a local pet store. He was a large crab, trapped in a magpie shell that was clearly too small for him. He was all alone in a tank with nasty blue "bag sand" and roughly 1/4-inch of standing water. She brought him home and I built him a nice little home in a 5.5G aquarium while I looked for better digs and maybe more crabs his size if I could find them. The selection of shells was pretty poor in the local pet shops, but we eventually found one the right size. Within a day living in his new tank, he was no longer ashy looking (his legs are now a nice bright red and his big claw actually looks purple.) He apparently agreed that the new shell we found for him was suitable and he's now cruising around with it. He switched back and forth a few times before he made his final decision, which was quite fun to watch. Everyone in my family has a different name for him, but I call him Herman.

My search for crabby friends turned up a Craigslist ad for a family trying to get rid of three hermit crabs. They were in a nice 40G breeder tank with a bunch of accessories (light, heater, glass top, lots of accessories). I just picked up the tank today and was pleasantly surprised to discover that two of the crabs were also large (one slightly bigger than our Herman) and the third is a medium. They bought the crabs when they were on vacation in Florida and did their best to keep them alive but they didn't want to move the tank to their new house. The larger crabs are in shells that are clearly too big for them, so it will be interesting to see what they do when I give them more options.

When I got it home, I cleaned up the tank and added some additional Eco Earth and water to the (very dry) sand. I removed the various painted shells and removed a bunch of pink aquarium gravel. When I move the tank to its final location, I'm thinking I will add a couple more inches of substrate to the tank (taking it to 6 inches) and I might try dropping in a smaller aquarium with 'molting depth' substrate as a sort of second level, using a seagrass net (which came with the new-to-me aquarium) to climb in and out.

I gave all the crabs a bath in the freshwater dish before introducing them. Herman did a little posturing with the smaller of the two large crabs, but the other crab eventually ran off. The smaller crab seems to get along with Herman, but Herman doesn't seem to like the idea of the little guy wearing his old shell - he actually saw the smaller crab looking at his old shell and came out to take it away from him! The biggest crab seems to keep to himself and isn't very social - I will have to work with him I guess.

I have more stuff on the way to make their lives better (including extra shells) and I'm looking into sources for better quality food. I am currently feeding them commercial dry food, supplemented with fresh fruit and veggies.

I am open to any suggestions on any aspect of my crabitat or food sources.

It sounds like your doing pretty good! I would certainly add a few more inches of sub, though. Your crab Herman sounds like a PP species to me. I cannot speak for the others. What kind of commercial food do you use? Some of it is unhealthy for them, but there are a few brands that work ok. Good luck!

I'm a pretty quick study and these forums have a lot of good info. I definitely want to build up the substrate so they can molt properly.

Herman and the biggest crab are both obviously PP. The other two have different coloring but seem to be within the normal color variations for Caribbean Hermit Crabs. I know there was a handy identification chart here on the forums, so I need to look for that to confirm. The humidity is up over 70% in the tank now, so their color will probably start to pop. They were all super active last night, checking out the new things in the tank and the biggest crab actually ditched the pointy conch shell he was in for one of the "muffin" shells I provided. The smallest crab still seems to be really interested in Herman's old shell, but he hasn't made the switch (that I saw at least). I have more shells arriving today, so we'll see how that works out.

On the commercial food, all I could find locally were "JurassiDiet Hermit Crab Formula" and "Zoo Med Hermit Crab Crunchies". I like to buy locally whenever possible, but the three pet stores in my area are clearly not well stocked with stuff for crabs. I reached out to an Etsy store for a sampler pack of better quality food, but have not heard back yet. I also have a decent store credit at one of the local pet shops, I may have to go check to see if they've restocked after the holidays - their shelves were pretty bare right after Christmas.

Welcome to crabbing and to the forum!
There are crabbers who don't buy any food specially for their crabs, they just feed from the kitchen! It is important to have a source of protein and calcium daily. I feed a mix of dry and fresh foods, it just works easier for me - and I'm a 'thrifty' crabber LOL. If you look in the turtle section of your pet store, you can often find things like dried shrimp. And in the bird section, there is cuttle bone (good calcium source). In the dog/ cat section, there are dried treats that contain only one or two ingredients (like Pure Bites cat treats, but don't get the ones with cat nip).
I wouldn't add a smaller area specifically for molting, as it could go wrong if all the crabs decided they should dig in that area - they would surely come across each other and cause problems. Better to have the whole tank deep enough to molt, with lots of room for everyone.

In addition to the dry food, I am feeding them various fresh foods I have around the house (Herman really liked the apples, banana, blueberries, pecans, and certain types of lettuce). I have a chunk of cuttlebone in there that they seem to like. My local pet stores were wiped out after the holidays and there wasn't much to be had for any animals aside from the most basic dry pellet foods. I was hoping to stop by the nearest one (the one I have a credit at) last night, but my schedule went a little off the rails.

My new-to-me tank is a 40G Breeder (36Wx18Dx17H), so it has quite a bit of 'floor space' for them. I will see about raising the substrate level to at least 6 inches as soon as I can though, which should leave a solid 10-11 inches for climbing. I thought I had a 50lb bag of clean play sand in my barn, but apparently, my wife did something with it.

Herman and the as-yet-unnamed crab of the same size really seem to like hanging out together. They had a little standoff when they first met, but I frequently find them together, facing each other, seemingly having a conversation with their antennae. All of the crabs are digging themselves into the sand a little and playing with the extra shells I gave them. Last night they all seemed to want to climb as high as they could.

I checked out those "Pure Bites" online, although I don't remember ever seeing them in the store - my cats would probably like those too.

FWIW, I added two 50lb bags of Sakrete Play Sand with the remainder of my 8qt bag of Eco Earth. I now have a solid 6 inches of substrate depth in the tank. I am guessing I probably need more Eco Earth, but my humidity bounced right back up to 80% not long after I closed everything back up.

Sounds good! You only 'need' more eco earth if you 'want' it! LOL!

crowtc, sounds like a great setup you have going. 40b's are really nice in the fish keeping world or with hermit crabs given their awesome large foot print per size/volume.

Like you say, I was surprised at how much my hermit crabs like to climb and how good they are at it, so you'll have to kind of split the difference of a suitable substrate depth and ways for them to climb up high. They are definitely not ground only critters.

One of the mistakes I made a few months ago when I got back into this hobby was jumping around from different sources for advice. There are a lot of great sources out there, but I think you'll find this one the most concise, no nonsense and easiest on the new keeper.

As an example, I followed different advice on my first 29gal setup, where you HAD to use a %:1 ratio of sand to EE along with a bunch of other amendments at specific ratios added to the substrate. Failure to do so would ban you for life from any sort of crabbery and crab protective services would immediately be dispatched to your residence.

I'm kidding... Mostly.

curlysister wrote: ↑

Mon Jan 24, 2022 12:06 am

Sounds good! You only 'need' more eco earth if you 'want' it! LOL!

JTKermie wrote: ↑

Mon Jan 24, 2022 11:19 am

Like you say, I was surprised at how much my hermit crabs like to climb and how good they are at it, so you'll have to kind of split the difference of a suitable substrate depth and ways for them to climb up high. They are definitely not ground only critters.

One of the mistakes I made a few months ago when I got back into this hobby was jumping around from different sources for advice. There are a lot of great sources out there, but I think you'll find this one the most concise, no-nonsense and easiest on the new keeper.

There are so many recommendations out there for a 'correct' mix, but nobody gives any hard measurements, so I'm just winging it. The substrate is mostly sand and has a good sandcastle-building consistency, but none of them seem to be very interested in digging yet, they seem to be more into climbing right now. I am considering the possibility of adding a large front-open tank on top of the 40B for the additional climbing room. (similar to the one Tmomma built in this thread.)

Note: Per multiple recommendations, I used my saltwater mix to wet the Eco Earth before adding it into the tank. I am using up all of the Zoo Med 'Saltwater Conditioner' I was gifted before I open the box of Instant Ocean I purchased.)

Humidity inside the tank is fairly constant between 80-85% right now, but the heaters I have are just barely keeping the air temperature at 75F. The crabs like to spend the day sleeping in a pile next to the smaller of the two heaters, but they are very active come nightfall. I am considering replacing the two smaller Zoo Med UTH units (One Small/One Medium) with a single larger UTH. I can get a Large (17"x11") Fluker locally, but I can get a Fluker Jumbo UTH (29"x11") on Amazon for a few dollars more. I would think that either of them, combined with an Inkbird controller should be able to get me a controlled temp closer to 80F.

JTKermie wrote: ↑

Mon Jan 24, 2022 11:19 am

As an example, I followed different advice on my first 29gal setup, where you HAD to use a %:1 ratio of sand to EE along with a bunch of other amendments at specific ratios added to the substrate. Failure to do so would ban you for life from any sort of crabbery and crab protective services would immediately be dispatched to your residence.

I noticed a very unfriendly and even hostile attitude on some of the forums/groups, particularly against 'new' crabbers. They apparently ban you for all kinds of rookie mistakes rather than try to help you do better. "You fail! No crabs for you!"

Thanks!