Most hermit crabs cannot live under water, they can drown, mould or both! Unless you know what exact type of hermit crab I would NOT take any chances on account of most don't! I hope this help, good luck!
It depends on the kind of hermit crab. if you find it at the beach it most likely needs water but if you find a land hermit crab they won't be able to breath under water, but land hermit crabs still enjoy being a little wet.
They hide in their shell.
no they will drown
As most people know hermit crabs have gills most animals that breathe under water have gills for example a fish. The hermit crabs gill's can work on land but in order for the hermit crab to survive they hermit crabs gills have to be moist....
no they'll drown
No. Hermit crabs have modified gills, meaning that they need 70-80% humidity in order to breath. However hermit crabs cannot breath under water; they will drown. It is important to have the humidity between 70-80% so the hermit crab can properly breath. Smoke is toxic to hermit crabs and will eventually kill them.
Land hermit crabs don't, they put them on damp sand at low tide, when the tide rises it carries the eggs away.
No, nor the other way around. One breaths air, one breaths under water for their entire life.
Hermit crabs sleep during the day, usually in dark coves and crevices. You will find them hiding under tree limbs, in small cracks in trees, in holes in the sand, in coral, and in rocks and driftwood on the beach.
No, it is not legal. You must have a permit to harvest hermit crabs from the beach even if it is only one. Additionally, the majority of the hermit crabs found on the beach especially in North America are marine hermit crabs and they will not be able to survive in the kind of habitat that is designed for Land Hermit Crabs. They need a full salt water reef setup and must live under water.
The kind of hermit crabs most people think of are Land Hermit Crabs. They live on land, and need at least enough water to submerge themselves. Land Hermit Crabs do need sea salt to keep their body chemistry balanced, and as such, need access to both salt and fresh water. Marine Hermit Crabs require a full saltwater aquarium to survive. Such tanks are elaborate, and should be researched thoroughly before purchase. Saltwater pets of all sorts are often regarded as difficult to care for.
In oxygenated water hermit crabs can survive for a short time. Straws can stay under the longest as their modified gills most closely resemble marine hermit crab gills. However, the time varies between the species. Generally a hermit crab will only be under for a minute or two. As long as your pool has an easy way for crabs to get out they are good at regulating when they have been under too long. A hermit crab will not drown if he has a way to climb out.