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New crabs and struggling to get this figured out

Posted: Mon Jul 13, 2020 9:40 pm
by ginrah
Hello all, We are new owners to 3 hermit crabs in a 10 gallon tank since May of this year. We have been doing everything we can for them and have seen them very little. One of the crabs (Sol) has dug himself under since the end of May. The second crab (Lune) has been out only for a few weeks but he seems to come out and then dig himself in for days or a week and then come out for a day or two and then dig himself in. The third crab (Jupe) we purchased later as Lune seemed to be so lonely. And they were together a lot when we got him. But they both have now dug themselves in for over a week.

I was told that they might be stressed due to the wrong temp or humidity. We have tried a few temperatures over the last few months between 75 degrees to 82 degrees and it is right now set at 79 degrees. It is a LOT of work to keep our humidity up as we live in a dry climate. So we bought a reptile humidifier. The biggest question I have right now is since the humidifier completely fogs up the terrarium is it safe for the crabs and will it stress them out more? We have a timer that will have the humidifier mist the tank for 10 minutes every 2 hours. We have a screen top. I have tried using items to close the screen top off and keep the humidity in btw.

We have been trying so hard to make this right for them so please be kind in your suggestions.

I figured out how to post pictures so the first one is with the humidifier on. The others are of our set up. We can't seem to find shells that they like so we have left quite a few in the tank. One crab went into on of the shells and then immediately left it and went back to old one. We have one successful shell change so far. ... 1czGjzTXwW ... 0Y2batvmaA ... 0bBC5yURMc

Re: New crabs and struggling to get this figured out

Posted: Mon Jul 13, 2020 10:01 pm
by HermitofHermitCrabs
It sounds like your crabs are being completely normal. Some just like to dig more than others.

Always shoot for 80 degrees and 80% humidity. If you're doing that and giving them proper food, freshwater, and saltwater there's not much else you can do.

Re: New crabs and struggling to get this figured out

Posted: Mon Jul 13, 2020 10:36 pm
by curlysister
I am unable to see any of the photos.

It totally sounds like normal crab behaviour, LOL.

A couple of questions about your humidity troubles. What type of substrate are you using? How deep is it?
When you said you have tried things over the screen lid, what did you try? What were the issues/ problems with what you tried?

Re: New crabs and struggling to get this figured out

Posted: Tue Jul 14, 2020 1:05 pm
by ginrah
I updated the link to the pictures so if you can try again.

The substrate we use is half the tank sand and half is Zoomed Reptisoil. It is about 1/3 high of the terrarium.

For the screen top we have tried a wet washcloth, we have tried tinfoil (only half though). We have a light that sits on top of half the top.

We are realizing that the humidifier/fogger is not keeping the humidity up as we are putting it on 10 minutes every two hours. If we leave it on the whole time i think its too much. We will try every hour now. Can anyone tell me if having the whole terrarium fogged up stresses out the crabs??

Re: New crabs and struggling to get this figured out

Posted: Tue Jul 14, 2020 3:30 pm
by curlysister
I still can't see the photos.

I don't know about the fog, but eventually it can cause flooding if you are needing to use it that much. Are you using the light for heat? If so, you might consider a UTH mounted on the back or side instead. If your tank is in a room with natural light, you don't need it for light. I would consider sealing the top of your tank with plastic wrap (Saran wrap, press and seal etc). The washcloth or covering only half the top won't hold in enough humidity.

Re: New crabs and struggling to get this figured out

Posted: Thu Jul 16, 2020 5:55 pm
by ginrah
Using the heating pad on the side and no lights, where is it best to put the thermostat probe? Under the sand or on top? Away from the heating pad on the bottom or the side?

Re: New crabs and struggling to get this figured out

Posted: Fri Jul 17, 2020 11:16 am
by GotButterflies

IMO - Hermit crabs are more active if the temperature is between 80-85, and the humidity is 80 and above. Are you using analog or digital gauges? IMO analogs aren't reliable. Here is what I use: Acurite guage from Amazon, digital, runs on batteries, tells you temp and humidity currently as well as low and high for last 24 hours: ... 184&sr=8-2
Substrate should be mixed with dechlorinated marine saltwater or dechlorinated freshwater to make the substrate sandcastle consistency. I personally mix mine with dechlorinated marine saltwater.

You can try to insulate around your heat pad with aluminum foil (shiny part facing the crabitat), then cardboard. Don't insulate over your heating pad if it is a zoomed. If doing the insulation doesn't raise your temperature, you might want to consider getting a better heater. Most of us use ultratherms. They are great heaters. or sells them.

Do you have a heat lamp? . IMO heat lamps are terrible at making the humidity evaporate, so I personally do not like them. A vast majority of crabbers use the ultratherms to heat the air instead of heat lamps.

What type of lid do you have? I personally prefer glass tops, however with glass tops you cannot set heat lamps on top of them. Heat lamps can crack glass lids. With mesh lids you can cover them in Press-N-Seal, or cut open gallon sized Ziploc bags and tape them to the outside with packaging tape to help keep the humidity in the tank.

Humidity boosters: Bubblers definitely do help boost the humidity. Double dish bubblers: ... r#p1030806

You can also add moss pits to help. You would use organic moss (as well as moss that is on the safe list), and moisten it with dechlorinated fresh water. Then, put the moss in a shower caddy or a glass vase laying on it's side so the hermits can walk in and out of it. Glass tops also help keep humidity in.

I hope this helps!

Re: New crabs and struggling to get this figured out

Posted: Mon Aug 03, 2020 6:10 pm
by CombatMist

Your crabs sound normal.

They are nocturnal, pps (post petshop syndrome), new home, new owner in progress. Hermes have large personalities in little bodies. Some are more active, adventurous, active at day. Could be sick, scared, wanting to molt. Ectotherms dont eat as much as warm blooded creatures. They dont need to eat daily (always offer it) so it's not unusual to not see them for days. They are also very good at covering their tracks and back filling holes to have no idea they came up, changed shells and burrowed with no trace. Try not to panic. Its probably ok. They go through cycles as we do. Want to stay up late a few days then back the other way.

You cant have too much humidity for the crabs. They are semi aquatic and beath air through gills. The only down side to 100% humidity is mold, decomposition and unwanted bugs. All preventable. My crabs have been more active at higher humidity.

My first lid was mesh. Couldn't get humidity over 60 no matter what I did. I have covered it with plastic sheet and went up 10 and then did full covered plastic sheet with 6 small holes to circulate some air and went up another 10. Now I'm getting 70-95% humidity. I now only mist tank if it drops to 70. Keeping humidity I think could be more important than making it.