Dying hermit crabs.

[Alyw77]

Hi,
A few minutes ago I think we lost our third hermit crab. We had 4. We take them out and for a little bit in the evening and let them crawl around on blankets on the couch. All are active. Last week when I was changing their food and water and checking on them I noticed had an exoskeleton fall out of the shell. I figured he was dead. Then I picked up the shell and turned it over and was deep inside. So I put him back and let him be. He didn’t move. He was by the saltwater dish and food dish. Just a few minutes ago I was changing the water and food and he fell out of the shell. I have enough substrate-sand and coconut. Those that were recommended here. Variety of food. What is going on please? I can’t even tell my 6 year old that another one is dead. He is dead I’m assuming. What am I doing wrong? I keep thinking they’re molting.

[curlysister]

I'm sorry your crabs are passing away.
I looked at some of your older posts, and there was at least one who had dug underground - did they come up from their molt? Did you get a thermometer/ hygrometer for your tank?
If you would like us to give more suggestions, you could copy and paste the questions in the emergency template and answer all the questions - that way we can see if there are areas that could be improved.

viewtopic.php?f=27&t=46102

[Alyw77]

One came up from the ground. This last one only hid under the coconut hiding spot and buried a little bit. Just like the rest in the tank. Not what I’d say underground. I’d like some recommendations on a thermometer and I guess I need a heat lamp. Nothing too expensive.

[Tim cuthbert]

For the thermometer/hydrometer i would recommend fluker’s thermometer/hydrometer. I use it and it works pretty well. And sorry your crabs died.

[Alyw77]

Do I need a heat lamp? House temp is about 71.

[Alyw77]

I have 4 bags of sand and coconut substrate. Expandable with water. Tank is about 20 gallons. I had 4 crabs before last night. 2 coconut shell hideouts and 1 driftwood hideout. Salt water dish. Freshwater dish. Food fish. Food is Tropical hermit crab variety diet, Zola reptile munchies omnivore mix with calcium. (Sand has calcium too). Zoo med hermit crab fruit salad, “Wholesome hermit crab food and tropical river shrimp in water. API aquarium salt and API tap water conditioner. No heat lamp. What am I doing wrong?

[curlysister]

Do I need a heat lamp? House temp is about 71.

Temps under 72 are harmful to crabs. You will likely need a source of heat. Many of us use UTHs (under tank heaters) which are mounted on the back or side of the tank. Heat lamps can work, but they tend to decrease humidity.

You will need a lid of some sort to hold in the heat and humidity. Crabs have modified gills and need humdity around 80%.

If your temps and humidity are both low, that could be why your crabs are not surviving.
Have you had a look at the 'basics' care sheet?

You will also want to read the 'water' care sheet, as the dechlorinator and salt you are using won't provide everything crabs need for long term health.

[Alyw77]

I just bought new equipment and changed the tank. I cleaned it out. Put coconut substrate on the bottom (as the bag said) and calcium sand on top. Total is about 4 inches. I put an under tank heater in the middle. I ordered a dual temperature/humidity gauge. We also added a new crab for the one that died. The tank is 30-40 gallons (I can’t remember). I took of the lid ( I put plastic on it-I always had). When I was done and put the crabs back in, one was climbing all around. I took them out later to give them a salt bath or bout 5 minutes. I woke up and felt the tank -warm and humid). 3 crabs were huddled together under a coconut shelter on the left forward tank. The other one dug under the substrate (not totally) in the back right of the tank. Is this ok? One had dug into 2 questions: I read that sand should be wet, then somewhere else that sand should be dry. I had wet it to sandcastle consistency. Also, I read different things. Temperate should be…? And humidity should be…? I really want these crabs to thrive and be happy and survive. What am I missing? I also bought canned shrimp in water. I’m going to cut up a strawberry later. I have a mix of food in the food tray. Salt and fresh water.

[Hermitcrab273]

when you give hermit crabs a new place they will start to huddle up and dig since it’s a new plus many other reasons. etsy,ebay and amazon has 4-15 dollar reptile thermometers. also when a hermit crab is deep inside its shell it’s scared or shy you can check out the care sheet to see what water brands and shells you need and a lot more

[Alyw77]

Thank you so much. I bought a dual thermometer/humidity gauge this afternoon. Reading about 80 degrees and 70% humidity. I have plenty of shells. I’m glad to know why one is in the sand and the other three are huddled. Thank you.

[jclee]

I just bought new equipment and changed the tank. I cleaned it out. Put coconut substrate on the bottom (as the bag said) and calcium sand on top.

Calcium sand is harmful. Switch out substrate to a mix using playsand from the hardware store.

[curlysister]

I just bought new equipment and changed the tank. I cleaned it out. Put coconut substrate on the bottom (as the bag said) and calcium sand on top. Total is about 4 inches. I put an under tank heater in the middle. I ordered a dual temperature/humidity gauge. We also added a new crab for the one that died. The tank is 30-40 gallons (I can’t remember). I took of the lid ( I put plastic on it-I always had). When I was done and put the crabs back in, one was climbing all around. I took them out later to give them a salt bath or bout 5 minutes. I woke up and felt the tank -warm and humid). 3 crabs were huddled together under a coconut shelter on the left forward tank. The other one dug under the substrate (not totally) in the back right of the tank. Is this ok? One had dug into 2 questions: I read that sand should be wet, then somewhere else that sand should be dry. I had wet it to sandcastle consistency. Also, I read different things. Temperate should be…? And humidity should be…? I really want these crabs to thrive and be happy and survive. What am I missing? I also bought canned shrimp in water. I’m going to cut up a strawberry later. I have a mix of food in the food tray. Salt and fresh water.

Glad to hear you are trying to make improvements!
Have you read through the 'basics' care sheet yet? It has info and a photo of everything you need for a tank set up. There are also care sheets all about water, humidity, food, etc. Not all dechlorinators and salts are appropriate/ safe. Crabs need a varied diet with protein and calcium daily.
The thermometer/ hygrometer is essential, so I'm glad you added that. 80 degrees is perfect (generally 75 to 85), but 70% humidity is too low. They need over 75% (and many of us aim for 80% or over so there is some wiggle room) in order to breathe.
As already stated, calcium sand is not safe for crabs, because it turns into cement when wet. Play sand is super cheap from a hardware store and is what is recommended. You can use all coco fiber if you would prefer (but play sand is cheaper for those of us who are thrifty crabbers LOL). Substrate does need to be moistened with dechlorinated water so that it is 'sand castle' consistency, ie- it holds it's shape.

[Alyw77]

Ok. If you’ve read my other posts I’ve lost 3 hermit crabs in about 9 months. I’ve been trying so hard. I follow all the recommendations and advice here. I closely monitor temp and humidity. I’m trying so hard. So about last week I noticed one of the first out of the three left was in his shell. Not curious. Not coming out gif his bath. I let him be. I didn’t think he was moving around the tank. I would pick him up occasionally to check on him ..make sure he was still in his shell. He had full regular color. Yesterday I noticed he was paler. He doesn’t move at all and is limp. I picked him up today when I was feeding and changing water, soaking the sponges and his pincer claw fell off. Is he dying too? Anything I can do?