Aquatic
(Rule)Description: Aquatic models can move within any area of water on the battlefield as if it were open ground. They are still subject to any special effects that specific terrain may have.
The models can march, claim rank bonus and be steadfast even when in water. If every model in a unit is Aquatic, and the majority of the unit is within water terrain, enemies shooting at that unit suffer an additional -1 To Hit penalty.