These are needed for hermit crabs to drink water. They are a must have. They also give the tank a natural "sea side" look, which I like.

Pros: hermit crabs need these

Cons: none

Sponges are a must have in a hermit crab cage! I would recommend this to anyone.

Pros: keeps cage humid

Cons: gets musty

First- hermit crabs DO NOT drink from sponges, they dip their little claws in a pool of water or they submerge their whole body in water to regulate their body's balance. A sea sponge is a good product to have because it causes the water to evaporate much faster which helps to keep the humidity level in the tank at a healthy 70-90%. Keep a sponge like this around, but make sure that your hermits also have access to both fresh and saltwater that is deep enough for them to submerge in. Remember, these animals live around the ocean- they don't drink from little sponges!

Pros: Helpful

Cons: Not to be used as advertised

This worked great as the hermit crabs can't cup water to their mouths but have to suck it. We learned the hard way that sponges must set on something like a shell to prevent the moisture from draining. Must also check often to keep the sponge wet.

Pros: works great

Cons: none known

These are the only way that hermit crabs can get water. They suck on the sponge. You will need to check the sponge at least everyday to make sure it has water on it. Also you will need to switch them out and give a fresh sponge everyonce in a while

Pros: Hermit crabs need these

Cons: none