Vaporeon

Vaporeon is a blue Pokémon with fins on its head, a ridge on its back and a mermaid-like tail. According to the Pokédex its fins will quiver when rain is on the way. It can also merge completely in water, because its cells are similar to water molecules.

Vaporeon is an evolution of Eevee, it can be obtained by using a Water Stone on the furry Pokémon.