What is the ruling on fishing with live bait, such as a live fish, and does the fisherman incur sin if an unwanted fish dies after being released from the hook?

It is forbidden to torture an animal unless there is a legitimate purpose or a possibility of benefiting from it without torture, such as caging a cat until it starves to death. However, if there is a purpose or benefit, it is permissible for a person to benefit from the animal, because Allah has subjected what is in the heavens and the earth to mankind. Therefore, a method of fishing that involves torturing the animal is not permissible if it is not the only means. As for accidentally catching unwanted fish, there is no harm in it, but it is not permissible to return them to the water if they are dead and others can benefit from them, because that is a waste of money.