You can breathe air and water.
You have darkvision (60 feet, blue and green) while submerged.
You have resistance to cold damage.
You have the ability to communicate in a limited manner with beasts and plants. They can understand the meaning of your words, though you have no special ability to understand them in return.
You gain the Magic Initiate (shapewater*) feat, and the Magic Intermediate (fog cloud) feat at level 3.
You gain proficiency in one Charisma skill of your choice.