3 New HM, 2 MIA for a month, 1 inactive but alive

[Mamaof3B]

Hello! Super new, and now a little super regretful. Did I get in over my head?

BACKGROUND: We (my sister) gifted my son 3 hermit crabs for his birthday. 3 smaller starter ones from Petco. We have a 20 gallon tank and used the recommendations on this forum for depth and substrate (1/5 play sand substrate) forgive me I don’t remember atm. The lady hooked us up and we have the saltwater dish, water dish, feed them the hermit crabs powdered food you can add water to, shady spots, heat lamp, climbing stuff. The temp and humidity gauge are almost always perfect if not me needing to squirt water a few times a day. I Saran Wrap the mesh lid to keep moisture. Coconut treats as well. We don’t have any sponges yet. 4 spare shells in different sizes but admittedly not sure if correct sizes but deff bigger than current ones. My blue hermit crab did check them out when I put them in. I don’t clean the tank but that’s because of the problem (they aren’t around.)

PROBLEM: Anyways, 2 of our 3 hermit crabs went underground the second we got them and we haven’t seen them since - it’s been a MONTH. They all seemed active and happy day of… and the third one (blue shell) is never moving, he just sits under the leaves. He does change position from one plant to the next. I took him out to play with us and crawl around basically twice since being home but then worried it stressed him out so I stopped doing that. But I checked the forum since we got them (March 30th) and there is no bad odor or smell of decay. I know they could be molting but, what are the chances the day I get them they molt?! And for a whole month?! Maybe the smell of death can’t get through all the substrate? Why isn’t my blue shell crab happy and out and about? I know they’re nocturnal but I’ve never seen him walk around unless I move him which I don’t anymore. Do you think the other two are dead? Why do they hate us? I feel very defeated and like we got a terrarium. Also I barely replace the food now because it looks untouched.

[Hermitsandplants]

new hermit crabs can be very stressed for while after coming to your tank, and unless the tank smells like rotting fish, don't worry about dead crabs. the smell is pretty strong so you would definitely be able to smell it. I would add more shells around the size your current crabs are. be patient with them and don't handle them until their first molt with you, and don't dig them up. btw sponges are not nessasary and can even be harmful because its a breeding ground for bacteria. I would still replace the food. some hermit crabs take awhile to molt, or just come up when you aren't around. most of mine are buried right now, and I haven't seen one in four weeks lol.
be patient, all crabs are different. Good luck and I hope they are okay!

[curlysister]

Welcome to crabbing and to the site!
Hang in there, you aren't doing anything wrong. As already stated, crabs from pet stores are usually very stressed when we get them. If they have been in poor conditions for a while, they may have put off molting as long as they can, and that's why they buried right away. Or they could have buried to de-stress. You are correct that if a crab dies underground, you often won't smell anything at all. If crabs die soon after we get them, it is nothing that we did - they were simply unable to overcome everything they went through prior to arrival in our tank. If a crab is dead underground, you gain nothing by digging it up, it wont harm other crabs in the tank. But if your crab is molting underground, you risk harming them greatly if you dig them up at a critical time. So while it is difficult, just keep doing what you are doing.
You will want to offer more types of foods. Crabs need animal protein and calcium daily. They can eat much of what we eat, and do best with a wide variety of foods - meats, seafood, veggies, fruits, greens, nuts, seeds, grains, eggs, eggshells, etc.
If it makes you feel any better, I have had crabs for almost 15 years. I have one of my original two, who is huge now. I got two tiny ones last year, and have no idea if they are both alive, as I haven't seen them both on the surface in about 6 months. I don't know if I keep seeing the same one go down and come back up from molting, or if one goes down and the other one comes up. I can't tell them apart, they are/ were similar size and were wearing similar shells the last time I saw them both together.