Bettas are air breathers as well as water breathers. They need to do both. I hope you are keeping the fish correctly though and doing regular water changes etc. Fish also stick their heads out of the water if it is going bad and needs to be changed.
it cleans the water and keeps the fish safe:):):):)::):):):):):):):):):):):):):):):):)
by putting the hook in the water and waiting for a fish
The fish will get sick and die.
The swim bladder keeps the fish upright in water.
nothing
The water may need to be replaced with clean, more oxygenated water. Of course, treat the water as you normally would before putting the fish in it.
it will die
By putting live mosquito lavae in the water with it. Or bloodworms.
it will probably die :-(
It is possible the fish could survive, however, it is more likely to stress out the fish resulting in death.
Fish use density in order to move in the water since they do not have lungs. When the density of water keeps changing, fish use it to move and thereby using less energy.
Fish body is of boat shape to balance itself in the water nature have given swimming bladders for fish.