How do you swim?Follow

Ok so I get this task to kill a fish, I go in the water and I can't go under for some reason. I look down and press forward and nothing. So I get near the fish ont he surface of the water and he starts attacking me. I try to attack back but it says I can't see my target. Sooo, question is, how do you go underwater or if you can't, how do you target things in the water so you can hit them?

Type /keyboard to make sure of your commands on your computer. On mine, z is for diving under the water and spacebar brings me back up. Once you are under the water, you will be able to attack your enemies. It's a little different under the water, but you will get used to it. Movement is a little slower at times.

Also, make sure you remember to buy aquatic breathing potion and /use it before you go under, or you won't live very long. lol