Smallest crab taking longer to molt than big ones

[crabbyvee]

So I have 3 crabs. The first one took 27 days to molt, the second one who is the biggest of the three, but still a medium-sized crab, took a month and 19 days. The last one to go down, Paco, is the smallest of the three and has been down Since October 30th of last year. The tank doesn't smell but I'm getting worried since the crab that was closest to his size took less than a month, and Paco is going on 3 months of molting.

So when should I start to worry? Theoretically Paco's molt should've taken a month tops. My fear is that maybe I didn't smell his death bc he was so small, and maybe bc he got eaten while underground by one of the other two? Does anyone else have an experience of their tiny hermit crab taking unusually long to molt?

[curlysister]

If a crab dies underground, you are unlikely to smell it through the substrate. That said, he may have come up and gone back down without your noticing. Unless you have cameras and watch 24 hours a day, you might not know that he came up if he was only up for a short time.

[hermitsinnc]

How certain are you that he hasn't come back up (and possibly gone down again, or been coming up at night and going back down)?
My little guy was gone for a while (longer than I thought he should take), but he did eventually come up. He's pretty shy and I usually only see him when I walk into the room at night after having been away. And, while in general, bigger crabs take longer to molt, it isn't a scientific/reliable/absolute way to be sure how long a crab's molt will take.