In the Crabitat

**If you are looking for the hermit crab dishes I make and sell, you can find them at my Etsy store. Thank you!

I’ve had a hermit crab obsession for a while now. And it actually started back in the 1990s when I lived in Florida and bought my first three. I did keep them in a big aquarium, but only provided gravel, a shallow freshwater dish, and pellets of “hermit crab food” from the pet store. I think they lived about two years. And it haunts me.

I have learned so much more about their care and feeding since that time and I like to think I’m making up for my earlier ignorance. These days, my tank is a 120-gallon (tall) with saltwater and freshwater pools, lots of climbing structures, and ten inches of sand—lots of space for them to dig tunnels and create safe molting caves. AND, I’m doing my best to learn how to breed them in captivity so that our pet hermits that we love don’t have to be captured and taken from the wild. Links to detailed record of my captive breeding attempts (by year) are below, followed by a running log from the current year.


Summer 2017 Breeding Attempt



August 15, 2018: I caught the first signs of this summer’s mating today. (I was out of town during the late June and July full moons, so may have missed some breeding then, but have also had no indication of eggs so far this summer so I believe this is the first breeding.) Everyone was a few weeks behind in coming up from their winter/spring molts this year, so perhaps this is just a reflection of that timeline. Last year’s first mating event occurred on July 31st, between Kermit and Artemis, so we’re not too far off that mark.

At first, I thought the female crab of this mating pair (the upside-down one) was Artemis, but after getting a better look I believe it to be Blue (who was a male when I adopted her in September of 2015—no visible gonophores—but had a super long molt last year (191 days–January to June!) and then subsequently had eggs last summer, much to my surprise.) She seemed very confused about what to do with her eggs last year and she never got them to the saltwater pool, instead casting them onto a piece of mopani wood. Hopefully she’ll be better equipped to spawn correctly this year. She and Kermit both came to me from a terrible pet store in Batavia, NY that has since (thankfully) gone out of business. There were so many crabs in a 20 gallon tank with a heat lamp, zero humidity, no water or food, and the only substrate was a 1/2 inch of hermit crab poos that no one had bothered to clean out for years. The crabs were big, but in thin, tiny little shells that barely covered their rear parts and they behaved like dazed and starved concentration camp victims after I got them home and into good conditions. It took them a long time to recover and learn to socialize, but they are now well incorporated into the colony and some of my largest long-term crabbies.

If spawning proceeds along last year’s timeline, I can expect zoeae on September 11th. That should be easy to remember.



The double kreisel in action.

September 10, 2018:

My larval setup is now fully prepped in readiness for the hermit crabs spawning which I hope will occur either tomorrow or overnight tonight. Here are the specs:

      • 35% salinity, verified with my handy dandy refractometer (freshly calibrated).
      • Temperature for the surrounding water is set at 83 degrees Fahrenheit and it’s taking two heaters to get that.
      • There are 2 1/2 gallons of saltwater in each of the side-by-side kreisels. I used Reef Crystals this time around for the extra minerals and calcium.
      • You can see that the nannochloropsis in the left-hand kreisel is doing well—it’s nice and green.
      • I decided not to keep the Chaeto (seaweed) in the right-hand kreisel—it wasn’t doing well in there and started looking almost moldy, so I guess that’s a no-go unless I try ordering a new batch.
      • I practiced replacing water with the big siphon, and that was easy with no issues.
      • I’ve mounted the two automatic feeders, one on each side and put a couple of plastic beads in there just to make sure they dropped okay and at roughly the correct time. (They did.)
      • My main crabitat is also tidied up, water changed, and shell shop cleaned since they will be getting a minimum of attention once the eggs drop. LOTS of poo in the shell shop, their new favorite loo.
      • I also upped the temperature in the crabitat after I checked my notes from last year and saw that it was up to 87 degrees just before spawning. The females with eggs are definitely congregating in the warmer spots, so it made sense to raise the temps a bit.
      • I have four gravid females currently: Blue, Artemis, Lola, and Garbo.
      • Oddly enough, Miriam and Kermit appear to be mating today, so that gives me hope about a second attempt, too.

      Now just waiting.


September 12, 2018

Still waiting, but here is a short video of all the crazy activity in my tank today. The females with eggs are definitely “migrating,” following that intense biological urge to make it to the ocean and spawn. (I don’t have the heart to tell them that their “ocean” is only six steps away.)


September 13, 2018

We have babies!!

Good Morning Spawn-shine!

This is what I awoke to this morning, finally. This first picture is from the saltwater pool in my crabitat, and those tiny white specks are the hermit crab zoeae. That gives you a good idea of JUST how very small they are. I sent the picture to my sister and she said, “What? those little bubbles?” To which I answered, “Exactly.”


And here is a video, shot in slo-mo, that (if you are patient enough to wait for it) shows a couple of them furiously swimming, legs and swimmerets going like crazy. So adorable.


And finally, a close-up of one of the babies. I believe that orange coloration is the yolk sac, which they will consume today, so no feeding necessary until tomorrow.









September 14, 2018

Artemis still has eggs today. This is now 28 days post-mating (Artemis and Kermit mated on August 17th). The eggs are extremely dark gray (you can see them as the uneven mass back in her shell on the right side) which means they are well developed and it’s time for her to spawn. The gray color is mostly a combination of the development of relatively large-for-their-size eyes and the dwindling of the orange yolk sac. They may hatch hungry. I would love to get a video of her spawning, but I’ll have to see how late I can stay up. If I miss it, I hope they survive until morning. I want to be sure that as many of Artemis’s larvae survive as possible. She is my most social and friendly crab. She comes to the sound of my voice and takes food from my hand. If I’m going to breed captive hermits, I want to do my best to select for the traits that will make them better pets than wild animals.

My first morning water change (1/2 gallon out of 2 1/2, so 1/5 of the volume) went fine. A little hectic with Molly (our new rescue pup) helping, but the first few days always feel 100% frenetic until I get in the groove (at which point it becomes only 75% frenetic). The larger tank volume is definitely nice, but I already get the sense that the Kreisel will be much harder to get and keep clean than the jars were. I fed three times today, small amounts, but I could make them even smaller and will try to do that tomorrow just to cut down on the waste. I feed a tiny drop each of Marine Snow, Nannochloropsis, and Decapsulated brine shrimp and watch it disperse. All three stay suspended well in the water column, which is helpful. Oh, I also hatched some live Artemia and added a dropperful of those to the tanks to encourage hunting behavior. I didn’t get a chance to watch for eating as Molly got very jealous very quickly.

Oh, and someone spawned in the fresh water last night. 🤢🤮😭
That was a sad and stinky affair (they can’t survive in freshwater). Thousands of dead and already rotting zoeae. I had to pull out the whole pool and clean it top to bottom. Too much stank.

Oddly enough, I think it was Lola who spawned in the freshwater (she was the one who dumped on the sand last year). And now that I think about it, all that weird guarding that Kermit had been doing of Lola for three whole days took place mostly near or right beside the freshwater pool. Was he trying to keep her from dropping in the freshwater?? I hate to ascribe too much “intent” to the actions of invertebrates, but this is certainly a curious possibility…

Off to do another 1/5 water change. Hoping that will hold them for the night. I have noticed that in the tank with the Nannochloropsis growing on the floor, the larvae appear to be dropping down and eating some of it. I’ll be able to tell for sure if their bellies turn green.


September 15, 2018

I awoke to find ANOTHER freshwater spawning catastrophe! 😭😭

So frustrated. I don’t know who it was, but there are thousands more dead zoeae in the freshwater pool. The whole bottom is gray with them. I’m nearly 100% certain that the freshwater actually causes their gut tracks to sort of explode, but—just in case!—ever the ridiculous optimist, I siphoned some out and put them in saltwater with a vigorous bubbler. I’ll check for survivors in a few hours, but I’m not really expecting any.

Last year I brought some back to life that had been cast on the sand and partially dehydrated, so there’s a slim hope. I also found some eggs on the rocks around the pool and on the edge of the pool. Figured those had a slightly better chance, so put them in a separate container with a bubbler. We shall see.

In the meantime, the other two tanks need food and cleaning and the puppy is desperate for attention. Gah! At least I’m not dealing with a hurricane on top of everything. I hope everyone in Florence’s path is staying safe.


September 16, 2018

Super busy day today so I just made a video of my setup to share. Trying to revive some of Artemis’s eggs before I head out to attend a friend’s book launch at Silo City in Buffalo.


September 17, 2018

Today has been a “shed day,” meaning they are shedding their old exos and moving into larval stage two. Great news, but a huge mess in the water that I’m trying to stay on top of—super hectic. Unlike mature crabs, they don’t eat their exo, so the water gets quickly clouded by “ghost crabs” the empty, white, eyeless exos and fouls quickly, too.


September 18, 2018: Day Six.

All appear to be at Stage Two now, except for Artemis’s which were behind by three days and then spent two days being “washed” and separated from all the muck that had attached to the eggs from the substrate. I didn’t really feed them during that time because I couldn’t even be sure they were alive. But I probably have about 300 or so that survived from her various egg-tastrophes. So. Much. Work. I sure hope she appreciates it. I was hoping to keep them separate so I would know which ones were hers, but it really isn’t feasible. Tomorrow I will add them to the kreisel tank where they will undoubtedly do MUCH better. (They’ve been in two Mason jars as I cleaned them—sort of like panning for gold—swish and swirl and jiggle, stare really hard and shine a light into the detritus, then swish and swirl and jiggle and repeat.)

I’m really amazed at the difference the kreisel tank makes. They are able to actually swim (instead of always being violently bubbled around), they can see and grab food easily, the volume of water makes changes easier, and I can see them so much better. (Still can’t manage to get decent pictures with my iPhone—they just move too quickly for the auto focus.)

I fed spirulina today and that was a big hit. They ate a ton. Green tummies everywhere. Their gut tracks are now clearly visible, which is good because I can confirm they are eating, but bad because they will soon be pooping, too, which means dirtier water.

The tank with nannochloropsis continues to be so much cleaner, and I’m not really sure why, because I’m feeding roughly the same.

I don’t really know how many I have in total. I’m guessing maybe 2,000, which is way too many to keep ahead of as they grow. I know I need to lower the numbers but it is SO HARD. What I finally did was take my glasses off when I poured off the top waste water. It means I’m losing a few every time, but if I don’t look, I can’t see them, and I tell myself it isn’t happening. It’s so tempting to think I can keep them all, but trying too hard to keep too many could cause me to lose them all—I know this. I just have a hard time pouring living creatures down the sink.

Anywho, still at it. Ordered more nannochloropsis today, got some extra baby whelk shells in the mail (might even order more) I need to get more salt soon (going through it fast!), and bought a grow lamp for the kreisel tank that I installed today and it kicks butt. I think that will make a big difference. Unlike others who have done this, I am turning it off at night, though. I’ll see how that goes, but providing a dark cycle is my preference.

Thanks for going on this ride with me. ❤️🐚🦀👶


September 19, 2018: Day Seven, still at Stage Two.

I had the idea today that if I started far away and moved in closer with the camera, it might be able to better focus as it came closer. Plus starting two feet away is a good reminder of just how very tiny they are. I’m liking this way to video document them. It was much faster and didn’t require editing. (Apologies for the rogue finger wave over the lens at the start.)

Artemis’s larvae are now added to the kreisels, split between the two. Their bodies are still mostly clear, and they are so much smaller—pretty difficult to see during changes. Hoping they will catch up and color-up. I still have the tank of last chances, too (the little hex tank) and that seems to be doing just fine. Trying not to look too close, throwing food their way and changing 50% water once a day. Hoping they thrive on neglect.

The zoeae are definitely pooping now. It looks like a little black stinger coming out of their back end and they do it a lot. I’m feeding and changing 20% of the water four times a day and that equals about four gallons of saltwater mixed per day. Using my two gallon bucket it’s not nearly as time-intensive as by-the-gallon was last year. It’s also not as precise, but so far we’re good. I’ll try to do a salinity check tomorrow. (And perhaps a sanity check while I’m at it.)


DAY EIGHT, September 20, 2018

Saw a few sheds today, but I think they were just a couple of stragglers still making stage two—maybe some of Artemis’s later eggs.

A few more deaths today, too, but still only a handful. And it was a stressful day for the larvae because I did a full clean of the kreisel tanks. They were getting fairly funky, so I emptied one and put all the zoeae in the other one, wiped it clean, then moved all the zoeae to the already cleaned one and cleaned the other one, then moved half of them back over.

I lined up the foods I’m feeding to show the breadth of their current diet. I will probably add and change a few things as they age and their needs change. I’m heading to my local pet store this weekend—they have a wide range of saltwater foods. I also need to get more Instant Ocean. Going through it pretty fast.

I’m changing 20% of the water and feeding four times a day. It takes about an hour each time, so I’m spending a minimum of four hours a day at this, not counting extra things like taking pictures and researching methods and writing updates. This project isn’t for the faint of heart, that’s for sure, but I’m still enjoying the challenge.