Underwater Combat

Impeded Weapons. When making a melee attack roll with a weapon underwater, a creature that lacks a Swim Speed has Disadvantage on the attack roll unless the weapon deals Piercing damage.

A ranged attack roll with a weapon underwater automatically misses a target beyond the weapon’s normal range, and the attack roll has Disadvantage against a target within normal range.

Fire Resistance. Anything underwater has Resistance to Fire damage.