Agile Swimmer

You flip, twist, and turn in the water with grace. Benefit:

Increase your Dexterity score by 1, to a maximum of 20.
You gain a swim speed equal to your walking speed. If you already have a swim speed, or if you are at least level 10, your swim speed increases by 10 feet.
You may hold your breath twice as long before suffocating, and if you start suffocating, you can survive for an additional 2 rounds before dropping to 0 hit points.