it depends how big the hermit crab is or the fish bowl
A crab that lives in the shells of other shell fish is called a hermit crab.
They cannot live with a land hermit crab because land hermit crabs live out of water so the fish would die (as you know) if it is out of water.
Fish.
if you have betta pellets, then you need to feed them 3 pellets once a day
BB pellets are not digestible and will create a blockage in the fish resulting in death. The size and the shape of most BB's closely resemble the prepared betta pellets and so could be consumed by accident.
fIsh sharks and cattlefiss
sharks and other bigger fish
birds,big fish
Freshwater crabs can be aggressive and may attack betta fish, especially if they are small. It is not recommended to keep them together in the same bowl to prevent any harm to the betta fish. They have different care requirements and tank setups.
The Hermit Crab.
Fish