a hermit crab
As it molts, it will grow. :)
Hermit crabs don't have a regular size because they grow, they don't stay the same size.
Yes, it will grow back.The body you see is actually a shell that the hermit crab sheds to grow. you can get all your hermit crab info on HERMIT-CRABS.com
No
you don't need to do anything a hermit crab will do it itself. if a hermit crab losses a leg it will grow back. it will grow back after molting.
It depends on the hermit crab but I would personally say just to be careful No the big one might hurt or bully the smaller crab.
yes
This depends on the type of hermit crab, along with the age, and in some cases, gender.
No, they live together in large groups of even hundreds searching for food.
No because the grass will contain a large number of viruses and bacteria, which will cause infection to the hermit crab.
No, they are invertebrates, meaning they need to molt their skin to grow an example is a snake, they don't grow, they molt their skin to grow, just like the hermit crab.