HCA: Hermit Crab Association

Suz wrote:Hello all. Boy am I glad you were the top google result! I've been visiting and reading a large number of posts for the last 7 weeks and here is the result of a trial by fire of a new hermit crab owner.

I am requesting for feedback and suggestions, please realize I read what I could and did some immediate corrections along with a lot of mistakes in between. The amount of knowledge on this forum makes it so that I almost wasn't going to post because the sheer amount of good information here but I still need help. At this point I'd like to make final corrections and I just really like the community. Also maybe the order in which I did things can be corrected and hopefully help someone else out in the future.

For the tl;dr portion these are the items I'm requesting confirmation/feedback/suggestions on along with everything else I clearly still do not understand, blindly missed and need answers on:
1. Confirm species

HM: These little guys look like PPs (purple pinchers, coenobita clypeatus) to me. They look pretty healthy to me, I don't see any obvious damage like missing limbs or antennae bits.
As you get your tank conditions on point (80F/80% RH), their colors will continue to darken. I think it has something to do with being able to breathe and function better. The crab in your first picture is definitely a PP, in some type of trochus shell I think. The crab shown in your third (and fourth?) picture is pretty orange looking in a magpie (aka Indian top, or Pica) shell. That orange color/tinge to his body combined with the black tips on his legs is typically a sign of just having completed a molt. Micros molt often. Molting is a good sign! So even if your conditions are not yet optimal, he was happy enough to molt, which is excellent. Even with horrid care, crabs tend to live 1-2 years in captivity, while with good care they can live 10-20+ years. And under good conditions they can easily double in size in a year, so be aware. The smaller the crab, the more often they tend to molt, and the shorter their molts often are.

2. Amount of substrate

HM: 6" minimum or at least three times the height of your largest crab, whichever is deeper. 5:1 playsand/coco-fiber moistened to sandcastle consistency with marine saltwater (Instant Ocean or similar product). You can use straight dechlorinated freshwater instead of saltwater, but mold tends to grow more quickly if you use dechlorinated freshwater to mix your substrate. Looks like you've got your substrate mixed up properly (from the first pic). What salt are you using to mix up the saltwater?

3. Depth of dishes

HM: Should be deep enough to submerge if desired, with a safe way to exit. Doesn't need to be buried in the sub, but you can. Most of us put glass pebbles or scallop shells in the bottom, with a plastic craft mesh ramp attached to a tupperware container with zip ties for ease of access. Also, nested tupperware bowls (with some rocks in the bottom one, water and such in the top one) are AWESOME for not getting salt on your fingers during water changes and not disturbing molting crabs. But as long as they can get water into their shells, that's the most important thing short term. I think in the wild they replenish their shell water from muddy puddles. Also, please don't forget to dechlorinate both your fresh and saltwater. The caresheet about freshwater, saltwater, and dechlorinator explains it well. Two popular dechlorinators are API and Prime, and removing chlorine, chloramine, ammonia, nitrates/nitrites, and heavy metals (if these things are in your water) is important to do.

4. How can I keep this dang tank at the right temp?!!?

HM: Buy the correct brand and size of under tank heater, and insulate your tank. You've got it mounted in a good location. Most folks will say buy the biggest UTH that fits above the level of your substrate and fits on the back of your tank. The UTH can cover the entire back of your tank if you want, you'll just have to add a smidge of freshwater to your substrate maybe a couple times a year to prevent it from drying out. For crabbing, Ultratherm brand UTHs are excellent (you can buy them from beanfarm.com or reptilebasics.com), and I think Flukers has a good one as well (I've only used the Ultratherms). Most other UTHs just don't heat crab tanks appropriately. Also, Ultratherm UTHs can be insulated (and I think the FLukers ones can be too), most other UTHs if you insulate them you could cause a fire. Fire is bad. Don't bend them, no matter the brand. And the Ultratherms are repositionable which is a plus. Maybe the Flukers ones too, I think... If you're worried about the UTH getting too hot, you can get a thermostat (I have a Zilla one), which won't let the tank get above or below a set temperature.

HM: For insulation of your tank, especially over your UTH, use 1/2" or thicker styrofoam. You can cover the styrofoam with aluminum foil first, then place it outside the tank and on top of the UTH. This will help direct heat into the tank. You can also use cardboard, but seeing as you live in the northern USA, I think you'll want something more substantial. Also Reflectix is a great product, it's like bubblewrap with two pieces of mylar on each side. You can get Reflectix and styrofoam board or any type of insulation board really at the hardware store. Layering is as follows: Crabs, glass tank wall, UTH, Reflectix or Aluminum Foil, Styrofoam or other insulating board. You can tape it all down with masking tape or packing tape, or really any tape you want. Some folks insulate only the tank back, some insulate sides, some the lid (if you have a mesh lid). It depends on your house tempearture how much insulation you'll need.

HM: A hint: Once you get your substrate mixed properly with saltwater, and you have a glass lid (or plastic wrap covered mesh lid), and you get your tank temperature up to 80F, any humidity problems may pretty much fix themselves. Or you can add airstones to the water pools. Lots of threads on here about how to do that.

5. Is the temp gauge I'm using okay?

HM: Looks like a good one, but if you're worried, you can calibrate it. It's always a good idea to calibrate these starting off, just to see if they're off and if so how much. Calibration instructions are in the care sheets.

6. Moving them to a 20 gallon tank and need general help

HM: Once they're up from their molt, you can just put them in. If they come up at different times, you can add them at different times, or at the same time, doesn't matter. Any agression issues, dip them both in the water bowl so they smell like they're the same tribe, and they should stop fighting if that's an issue.

Our story begins 2 months ago...

My step-daughters won 2 crabs from a school project/contest back in April or May. We picked up the girls half way between Illinois and Colorado for the summer and surprise surprise we were handed a critter cage with 2 crabs, 1 coconut hide, 1 red climbing stick, fish aquarium gravel and a good luck. Sigh.

The smell was horrific and we the windows went up or down for 9 hours... I began to goggle hermit crabs as we drove and I landed here (thank goodness).

First thing we did as soon as we arrived in Colorado on June 9th (before we even unpacked the car) was remove the crabs from the critter cage and placed them in a plastic shoe box while I assessed the situation. I came to find out the girls had been giving the crabs tap water and sprinkling "hermit crab food" in their cage and had given them a couple of rotten grapes. They had been living on gravel and sitting in a pool of tap water and rotten food for 2-3 months!!!

Cleaned the gravel, items and chucked the cage. Luckily my roommate had a spare 5 gallon tank that he uses for transferring fish laying around. Sadly, I did not read enough at that point to realize the gravel was still a very bad thing for them. At that time we put them in the aquarium, bought a mesh lid, the correct type of water (drinking only) and called it good. We decided to see if the crabs would even live through the night and next few days before taking the next steps to ensure their happy survival. They survived the night and the rest of the weekend, it was time to get serious about these crabs and give them proper attention.

I came back to the forums and read some more. Every time I read a post, article, etc. I felt for sure the crabs would be dead by the next day. These are the most fragile creatures on earth!?!?! Why would people want to take care of them and have them as pets was always my first thought. Wrong water, dead. Wrong food, dead. Wrong temp, dead. Wrong substrate, dead. But let's face it if they survived living in that plastic cage for 2-3 months they could survive just about anything.

Monday (6/12) came around and I decided to see what temp/humidity the tank was at and began to correct it. Colorado being one of the least humid states, I knew this would be a super struggle. My first way to correct this was moisten a cotton towel and place it on top of the cage, it provided humidity and darkened their home to allow them to destress. I got the humidity from 40% to 65% within a day, which by my standards was pretty dang good compared to the critter cage but still not good enough. The crabs seemed more active with the temp and humidity being a bit better. I've keeping it between 82-86% with a glass lid that I crack for airflow.

HM: You don't need to crack the glass lid for airflow. If you just open the lid once a day and change out their food, that's enough airflow for most tanks. Keeping the lid closed will really help keep your humidity up. Anything over 80% is fine for crabs. Mold grows well somewhere in the 90s and up, but it doesn't bother the crabs, just people. So if your humidity tops out, I wouldnt' worry too much about it...

Read a few more articles...

Started feeding them correct food being raw veggies, fruits, proteins, nuts, egg shell, etc.

Around Thursday (6/15) my next step was to figure out the types of crabs we have and if they needed saltwater or not. I settled on them both being PP as they are the most common and looked like most peoples pictures. I'll be honest at this point I'm still not 100% positive in my ideas of which species we have but I'm pretty sure I'm correct. At the same time I had read up on them needing a number of shells in the tank so they could easily change as needed/wanted. Growing up I was an avid beachcomber and my mother had a large collection from beach combing as well luckily I had around 30 shells of what seemed to be a good size for them. Placed a few shells in the tank and BOOM, the smaller crab went to examine them all. They had been shoved all over the tank and samples taken from the shell for food or I assume that's what they were doing, scratches were all over them.

HM: They're probably desperate for new shells. It's like a mental hangup for them. Preferred shells for PPs are listed in the Shell Guide. Any type of turbo (mexican, tapestry, green, etc.) is preferred, and occasionally apple murex, if it doesn't have too many protrusions about the mouth.

These guys are starting to grow on me... I hope the girls don't want to take them back home.

HM: If someone is molting, and the tank gets moved, the molter will have to be dug up because if the molt cave collapses the crab will suffocate. Digging up molters is REALLY not recommended, but occasionally it has to be done due to moving. Several threads are on the forum about how to do this safely, if you absolutely have to. But hopefully they can become your kids' pets at your house.

Friday (6/16) I went to home depot and bought a bag of sand as I knew I needed to get them digging in case it was close to molting considering the shells were being shoved all over the place and they had been receiving proper food. Brought home the bag, cut it open aaaaand, I bought gravel not play sand. Ugh, I felt so defeated over something so trivial.

Stalled for another two weeks as what's broken doesn't need to be fix, yes I'm a bad person as they still did not have salt water.... Read some more here and there. The fourth of July came and went and our house guests were gone. Spent another 4 hours worth of reading and decided to fully submerse into a crabitate to make sure I bought the correct items... Shopping time!

Ordered: Substrate (sand and coconut fiber), saltwater mixture, sea sponges, moss, coconut fiber and heating pad. Everything arrived within a couple of days. July 10th was a big crab for the crabs...

I added 2-1/2 bags of substrate mixture to the tank and measured a crab against the outside to make sure it was 3 times as deep as his shell. Yes, I added it over the top of the rocks - hey, I'm still learning. I made salt water and measured the salinity, good to go. Made a moss pit, attached the heating pad, cut up some sea sponge for them. Gave them a fresh and salt water area and placed them into their newly remodeled home.

They went bezerk overnight. Sea sponge moved into the hide, tunnels were formed, both water dishes were dirty from use and moss was everywhere and an entire almond had gone MIA. I was so elated, I gave them a better home. I cried. Cleaned water dishes and food daily and everything was being put to use. It was a good week. The 4 watt heating pad has been a bust, zero temp change in the tank, still working on this and need help.

HM: Yea for their new home!!!

I started reading more on behaviors and molting, etc. I marked the calendar (July 12th) with the large shell having gone down for molting as I had noticed the tunnel hadn't moved for a few days and decided to just keep reading. Came down in the middle of the night and wouldn't you know it a sandy shell was running across the sand to the salt water dish, that sneaky crab! Read some more, oh... He might just be destressing or just likes to dig. Hmmm, I wonder if I put enough substrate in for him?

Friday July 14th came around and I decided to keep reading and make sure it was really the right size tank, I had decided at the time that they were micro's and a 5 gallon was okay based on the chart. I have since changed my mind on their size and the size of tank they need. I feel like they are small sized, I've printed out the sizing chart and I'm waiting for them to be surface side so I can measure them. I started looking on CL's and I've found a 20 gallon tank for $15 and it has a glass lid. Questions to follow... I guess it's go big or go home also I might want some more crabs, heh. Have I mentioned they've grown on me?

So here is where I am at... Mr. Crabs the large shell is not molting he just digs and comes up at night. Sheldon pretty much lives in the moss pit and comes out a few times a day and a lot of the night.

I will be picking up the new tank on Sunday and beginning the transfer. With the glass lid, will it be okay to keep it cracked up for air flow? I'm hoping the glass with help with the humidity and temp. With it currently only being 2 small crabs and a 20 gallon tank how much substrate do I need? Still 8"? I'm not thinking it needs to be more shallow with less crabs, I'm just wondering on the crab size to depth ratio. What watt/size of heating pad do I need to be looking at? The placement of the pad is my next question. I don't want to overheat the moss pit or the hide.

HM: Glass lid does not need to be cracked open, see my comment above. Will definitely help keeping temp and humidity up. Still need same depth of substrate you had before. See above comment on substrate depth. See above comment about UTHs to address your heating pad size/watt question. More is better, since you live in the north, and in the winter it gets cold. Overheating is not very likely, in my opinion, but if you're worried definitely get a thermostat. See above comment on thermostats. Back of the tank is a great place for the UTH. You can move the moss pit if you're worried. My moss pit is a hanging basket mounted on a Command hook, with branches they can climb to get up to it. So going up is one option if you've run out of floor space.

HM: If you're looking for more crabs, you might try to adopt rather than purchase them from a pet store and support the pet industry. Often they can be listed on Craigslist, or some other online sales websites. HCA Adoptions forum is a great place to start looking if you're wanting more crabs.

This has already been much longer of a post than I had intended and it's time to pick the girls up from day camp here are some pictures for now.

aussieJJDude wrote: I would keep an eye on that red cholla, I've got them but mine are entirely made out of plastic. But according to a few US crabbers, yours seem to be painted or dyed cholla branches...? IDK, if it is true, but I would just mention it just to give you a heads up regardless.

Suz wrote:Oh boy, I am so excited! I went ahead and finished up with the freshwater instead of salt as the humidity is so low in our state that I doubt I could get it above 90% even if I tried really really really hard.

So, I have the tank set up. The smaller PP was hanging out top side and was the first to "move in" and quickly checked everything out and claimed the coconut hide. The larger one came up during the night and I quickly grabbed him before he could escape, I dunked him in their water dish as to not have him smell like an intruder as it had been probably 12-18 hours between adding them both to the tank. How guilty does it make you feel to dunk your crabs? I was thinking, please don't hate me! It must be like a polar bear plunge for them.

I ran upstairs to let Gabe know that the second guy surfaced and had been transferred! We ran back downstairs and that sucker within 2 mins I was gone switched shells (Babylonia), flipped the sea sponges upside down, checked out the moss and went right back down into the substrate, ha.

Today I'm off to buy even more shells for them, I've gone through my collections and far too many of them are undesirable for crabs either from weight or style. I will also be purchasing climbing items, cholla, etc.

I've ordered the ultra therm uth for the tank hopefully that will be the last piece to having a happy functional tank.

I'm a visual person so here is a new picture. How do you guys feel about the slope? I've noticed a couple setups with slopes and most without.