HCA: Hermit Crab Association

Hello, it's been a while since I've contributed to this forum. The crab I introduced in Dec. 2019, Busy, seems to be thriving still. Since that time, I have continued taking her out of the cage for an hour or two, pretty much every night (generally while I prepare/eat dinner). This has been a big part of my hermit crab experience so I wanted to share it on this forum.

My biggest concern has been safety. There are all kinds of potential hazards. It can be a bit stressful having to worry about her getting tromped on by my wife (which almost happened once), or by me (or sat on by me on the couch, where I often let her walk around). And I'm terrified of her getting lost or stuck in some inaccessible place. I check on her every few minutes, and what I've learned is that if I mumble to myself, "She's heading towards the dog food", etc. it fixes it in my mind and makes it a lot easier to keep track of where she is. I'm most afraid of her getting behind a heavy appliance like the oven, fridge or washing machine, because it might be impossible to extricate her safely. I close doors to rooms to limit where she can go. The other terror is the removable vents in the floor, a one-way trip to the furnace/AC! Can't imagine why anybody would remove them, but my mind tends to imagine horrible scenarios so it makes me nervous and I always check. Closets are a big worry too, but easy to close off.

There are lots of other potential hazards. Maybe it's not healthy to be out in the dry air (we're in Colorado). Quite often I bring her out first to the bathroom when I am heading to the shower, which should be a nice humid/safe stroll for a crab, but then I bring her to the kitchen/dining area when I am starting dinner. There are fallen leaves from houseplants, which she sometimes nibbles on, and those could be toxic. She also likes to eat the dog food crumbs around our dog's dish, and a couple of times, has climbed inside it! One time she climbed onto my plate (I had been eating on the couch) and ate some crumbs. I worried afterward that there might be something unhealthy for her on my plate. But the habit I've developed, is to basically let her nibble on anything, but not to give her more than a couple minutes with it (all things in moderation). I imagine dog food might have toxic unknowns though (pesticides etc.). She really seems to like soft plastics, and one time she nibbled a big hole in my earbud, which also concerned me. But I also feel like having the opportunity to poke around on the floor might also give her trace nutrients she is not getting with the 3-4 commercial crab foods I feed her. But really, I started this from feeling that she would enjoy having places to explore.

One of her favorite places to go and settle down is where the wifi router and internet modem are, behind the TV. I suspect they are giving off warmth that she likes, although where she sits between them, doesn't seem noticeably warm to the touch. She also likes to climb on a wicker magazine basket. On the couch (which has fuzzy texture, not leather or anything), it is quite easy for her to climb around and even upside-down. Sometimes she runs into bits of dog food that she had transported there on an earlier night and settles in to munch. (On a few occasions when I pick her up to limit time with the plants/dog food, I've noticed that she's still holding on to a piece.) Of course she leaves crab poops here and there, something to clean up but not really a concern, as they dry up soon enough.

The dog is another potential worry, but our dog is a real scaredy-cat and always gets up and leaves when she comes exploring too close.

Once in a while I worry about a sudden blackout happening (e.g. during hot nights when the power company is under stress), so it's important to know where to grab a flashlight so I could retrieve her ASAP.

I've taken her outside on a handful of occasions, and she seemed to enjoy exploring in the lawn/weeds, but obviously that's really fraught with what-ifs and I have to keep even more of an eagle eye on her, so it's kind of stressful.

Anyhow, I am curious if anybody else has experiences like mine. I'm not sure how I got so hooked on this habit. Having written all this, I'm guessing somebody will tell me walking the crab is a bad idea. Looking at my journal, the walks became much more frequent in summer of 2019, and have been basically every day since. She last molted in Aug. 2020 and still seems pretty active in the cage so I'm supposing she's still healthy. One thing though, she hasn't swapped shells in a few months, so currently I'm shopping for new shells.

That sounds fun your little crab is having the exploring experience they would not get in the tank. I would be carful about the dog food though and you should research the plants. It must be so fun walking the crab!

Thanks for sharing your experiences and perspective on this.

It sounds as if you keep a close eye on her, and I'm sure as with any animal movement is healthy (which is why I do all I can to encourage maximum movement in our tank). But you are right that dry air outside the tank is a danger to her. Because they breathe with modified gills, they really do need a good percentage of humidity (generally between 75 and 85 %) in the air in order to extract oxygen from it. Temperatures cooler than around 75 degrees Fahrenheit are also a problem. But if she has been regularly having this "out time" and still seems healthy after two years, then it seems that it may be working for her.

You say she last molted last summer; I'm guessing that must mean she is pretty big?

Swapping shells isn't necessary if she is happy with the shell she is wearing. She will only need a selection of new ones when she is ready to molt and grow more.

Most dog food has preservatives and very likely pesticide residues in it that are definitely not recommended, but again, if she's been having a bit all along and seems fine. . . . ?

I have a question. From the way you describe her behavior, you seem to indicate that she knows the layout of your house and repeatedly visits certain places (the dog food bowl, the place behind the TV) to do certain things. Do you get the sense that she remembers where those things are and chooses to go there, or is it more like she is rambling around, but when she encounters those things she enjoys them?

Thanks for the questions, and I appreciate the nudge to be a little more cautious about the dog food. My early instinct was toward caution, but after a while I got lulled into complacency, and distracted by the charm of a hermit crab elevated to the status of an "out of cage" pet, on the same level as the dog.

Regarding temperature. I don't have an undertank heater, and think I'll look into it. Indoor house temperature is 72-73 in summer and 70-73 in winter. I think her fondness for the wifi box is trying to tell me something. Also the magazine basket sits next to a heating vent, and she often has settled in there indefinitely (until I pulled her out), again, no doubt enjoying the heat. In high school I moved (with my hermit crabs) to a new house that was kept at a chilly temperature, and they lost limbs and died.

As for humidity, I agree, based on how they breathe it seems crabs would be very dependent on it. I have an odd anecdote here. After I left home my mother took in renters. One of them had a hermit crab who disappeared. It was found weeks or months later, wandering around outdoors. So I suspect they (or some of them anyway) can go through dry spells surprisingly well. I do keep her cage rather humid (with a coconut-fiber soil from pet store), and there are growths of mold & algae so I probably lean toward too much humidity. Maybe she enjoys an hour or two each day to "dry out"! Just a speculation.

DragonsFly, I've been thinking about your last question, and I don't have a great answer for it. In general I release her in the middle of the main floor where she has an option of going any direction. There is perhaps an initial half minute or so of "getting into the mood for a hike" during which there is some randomness in what direction she ends up. Once she has really got going, she goes more or less in a straight line. So it is probably pretty random. Each evening I pick her up perhaps a half dozen times to get her out of trouble, and I can "somewhat" control where she is likely to go, just by position and by pointing her in that direction, but she often goes off at an angle I didn't expect. Once she starts to perceive either dark places, and/or makes contact with walls etc., then that will guide her further.

One thing I can say for sure, her preferences seem to fluctuate. Over the past couple years she goes in and out of "phases" lasting a few days or weeks where certain types of activity or locations seem to predominate. Sometimes she is really drawn to the spider plant, and will just sit under it chewing on leaves, and when I pull her out (against resistance) she brings a piece along. It's been a while now, since she's spent time there. There was a period where she climbed on the magazine basket quite a bit and kept burying herself under the newspapers. There was another period (recently) where she would just head for the corner of my couch and hang out under a pillow (to my disappointment - not "having adventures" as I wanted). (But that may have been due to a crumb of dog food there, that I wasn't aware of at the time.). I sort of wish I kept track of it all, but perhaps not, as I tend to over-document things as it is! No doubt, part of the explanation is just my pattern of behavior, in terms of where I place her.

But, looking at my couch as a starting point for example (where I typically place her when I settle down to eat dinner on the couch), she definitely does a lot of "deciding", walking back and forth sometimes, then choosing an edge to climb down, then has several options, number 1, sneak over towards my wife's couch (perhaps napping), in search of a dark crevice behind or under her couch. That's a "no go" as far as I'm concerned so I always grab her (also the dog is often sleeping next to it). Option 2, go behind the TV and curl up next to the wifi/modem boxes. Here's an example where I observe unpredictability, even "sneakiness". Lately, I've grown used to her settling in there until I put her back in the cage. But sometimes, after an unpredictable period of time, she'll just make a beeline out of there, and head toward option 3 or 4. Number 3 is a small hallway with several doors (all closed for safety) to laundry room, etc., and she gets kind of trapped in that hall, making her way around the edge, ultimately finding her way back to one of the other options. Option 4 is a big front room with piano and book cases. I have stuffed books behind the piano to keep her from getting to the backside of it (not sure if there are any danger spots on the back of a piano). So it is a pretty safe room. Here, she "normally" traverses the edge in a predictable way, working around the front door, some house plants (debris to munch on), etc. However again here, sometimes she heads off across the middle of the room, straight toward the piano, or toward her cage area. So this is definitely where she's made some kind of "choice".

Option 5 is the kitchen area, with a hardwood floor, and this is where we have spider plant, magazine basket, dog food dish. Usually the first place I release her in an evening is on the hardwood floor, because I am preparing dinner. Often she heads toward option 1 (wife's couch), but, quite often will go for one of the destinations I listed in the kitchen. One time she got into the kitchen pantry. Most often she navigates along the edges of walls, but, it's not that uncommon for her to cut across an open space.

In general, during her outings, I only need to check every 5 minutes or so, during which she might travel a few feet (just guessing). Very occasionally, she'll go *under* my couch, or under the coffee table next to it (it has a low shelf so could be a cozy hiding place). Both fairly safe (unless there is a hole in the couch to climb into?), but sets off my alarm bells when she is not easy to monitor visually. In that case I grab the flashlight to make sure I can keep track, and sometimes try to chase her out using a backscratcher!

I forgot to answer a couple other things. Yes, she's "big" by my standards - current shell opening is about 1-1/8" I think (1" in some directions). (Have had her for over 10 years, I'm guessing). But I think she's outgrown all her shells. Last week I made the rounds to the 3 local exotic-pets stores and did find a shell that caught her interest, she wore it a couple times but is now back in her "usual" shell. She used to swap quite a bit (for "fun" it seemed), but not so much lately. I have been scrutinizing the options at deltonaseashells.com, and will probably try my luck with some of the "3 to 3.5 inch" shells there, e.g. "jade turbo shell (medium)".

One thing I meant to add - ever since I started this "daily walks" ritual, she has become much more habituated to me. It's not like before (and I recall with other crabs) where a human approach caused her to close up, and I would put her down somewhere and have to wait a period of time before she comes out of the shell. She is very outgoing and when I carry her about, her legs are all reaching and scrambling; so what I do is hold her shell with one hand, and let her legs lightly tread on my other hand without letting her quite get a grip (I think this is safest so she does not find a way to climb on me and "jump" to the floor while in transport).

You should make a little leash for her for when you take her outside. It would look so cute! But i wouldn't put it on the crab itself but tie it around the shell. I am going to make one for my hermie when he/she is bigger.

Deltona Shells is good to deal with; they will (or at least they used to) measure the OPENING of the shell for you, which is the most important thing for hermit crab shell purchases. You will notice that the size of the overall shell goes up immensely with just a very small increase in opening size.

Thanks DragonsFly. Based on her current shell (approx. 1-1/8" inside diameter of opening, measuring along longest axis), other shells she's used, and a huge shell she tried once and didn't like (1-7/16 x 1-3/8), I am aiming for shells in the 1-1/4 to 1-3/8 range. Deltona shells gives openings for some of the shell types/sizes, but many of them list "NA" inside. So there is still a fair amount of guesswork involved. There's a cool "shell sizes/openings" thread on this site, with graphs that may help with this somewhat.

Back to walks, though - lately she has been crawling on the ceiling again, after a long hiatus. I wonder if it means she wants fresh air? Or just, feeling hyper? When she is doing that in the evening though, I tend to skip the walk, because I'm not comfortable trying to pry her off of the wire cage, and also, seems like she's getting enough exercise that way

What is your set-up like? (Do you have a thread here describing your crabitat or with pics?)

She is in a 10-gallon tank with a plastic tree (that she uses to climb to the ceiling), a dish of distilled water, a dish of salt water (using Instant Ocean), about 4-5 inches of damp coconut fiber substrate. I introduced her a couple years ago in the New Crab forum:
viewtopic.php?f=28&t=121535&p=1089120#p1089120
I also have a plastic shelter that I added a few months ago that she likes to sit under and climb over - it is a half-cylinder, shaped like the bark from half a tree trunk.

I feed her a mix of All Living Things Variety Diet, Crab Island Fruit & Flower Crab Food, Fluker's Strawberry Treat, sometimes with a sprinkling of National Geographic Shrimp & Lobster Pellets. She is mostly crazy about the strawberry treat. These are all powders/flakes. I also dust heavily with some pinches of All Living Things Calcium Supplement.

I must confess I have not been good about varying her diet. I tried (dried) mealworms, and she kind of dragged it around but did not eat much of it. I'm nervous about using scraps of fruit/veggies from my diet since I often eat produce with pesticides. I wonder is the inside of a fruit safe, even if the outside has pesticides? Tried egg shells just today and she loves it! Sometimes give her crab shells (e.g. after a Dungeness feast) which she used to enjoy.

Well, if she only has a 10g, I'm glad she gets to get out. That's a tiny box indeed for an animal that travels miles every night in the wild! She sounds pretty big; with 4-5 inches of substrate (which you definitely need for a crab that large, or preferably more), there's not much room left in a 10g. So I'm glad she is doing okay with her "out-time." I suspect that more movement is a good thing for them (as with any animal!), and that being confined (in any size tank) is probably not optimal for their health, but it is surprising that she has been so robust even in quite a dry climate. You may just have a particularly hardy crab there!

If you are looking for a new favorite for her diet, try bloodworms. You can find a little container of them in the fish section of a pet store, and the crabs love them (mine didn't think much of mealworms either, but they love bloodworms). If you don't buy organic fruit/veggies it's probably better safe than sorry not to give her stuff with pesticides, but you might try occasional offerings of something fresh from the very interior of whatever it is (hopefully that would have less pesticide, although if something is grown with pesticides they could theoretically be anywhere in the plant). You can also offer a little bit of cooked meat now and then. And plain cuttlebones (from the bird section of the pet store) are a great source of calcium and crabs seem to love them. Shrimp tails are another favorite here.

Thanks again for sharing your experiences, very unusual and interesting. Best wishes.

My goodness. I thought the 10-gallon tank was a palatial mansion for a single crab! At least at the time I first set it up. You should have seen the little plastic box where she spent her first couple years. Okay, I see from the care sheet that a 75-gallon is probably in my future. I will need to wait for my wife to be in an especially good mood before starting that conversation.

It seems to me that a "vertical" style tank is preferable because crabs climb, and they (especially a single crab) only need one place to molt at a time. So it would be wasteful to have a tank 4 feet long, filled with say 6 inches of substrate.

You'll need more like 12 inches of substrate eventually, and there is something to be said for allowing a good amount of space for burrowing, also. Mine dig all the time, and that's probably better exercise than climbing, or at least as good, as well as helping them feel more comfortable for a molt. I have my 2 crabs in a 120g high, with 12 inches of substrate on the "jungle" end, tapering down a bit to about 10 inches on the (all-sand) "beach" end. This still leaves lots of room for climbing apparatus. You can always put toppers on tanks, too, to "build up," if you have a very active climber.

If you are patient and willing to "wheel and deal," you can work your way up to a larger tank in the second hand market. It is a great advantage that hermit crabs do not need a water-proof tank, so you can get a "leaker" for a lot less than a tank that will hold water. As long as there's no broken or cracked glass, it is fine if it does not hold water. I got my 120g by scouring online "flea market" type sites for second hand tanks. I started with buying two 30 gallon tanks that nobody would buy because they were completely encrusted with nasty algae; I bought them both (one with stand) for $20, cleaned them up and sold them for more than I paid for them, then kept re-investing that money in used tanks to clean up and sell for a bit more or trade up, until I ended up with a 120g high with a nice strong wooden cabinet stand. All told I probably spent $100 for the full set-up I have now, but it did take me 4 or 5 months to work my way up from the first two nasty 30g tanks to the 120g. Patience is a virtue!

What is the meaning of "high" in "120 gallon high"? Google is not helping me here.