Easy mod idea — spear guns

I've always wondered why they added fish entities to the game but not an easy way to harvest them. I think a simple and useful mod idea would be to add fishing spears and a spear gun. The spear gun should do enough damage to take out fish with a single hit, and it should only fire when the player is underwater. It should probably also function like a crossbow. The spear munitions could use a similar recipe to arrows but use string instead of feathers. This would make them easier to craft which would make up for how situational they are.