Aquatic Breath

 
Prerequisite(s): Ability to cast 3rd level spells>
 
Benefit: As long as you have a water spell of 3rd level or higher available to cast, you can breathe normally in both air and water. This supernatural quality requires no activation. As a secondary benefit, you gain a +1 competence bonus to your caster level when casting water spells.
 
Source: Complete Mage