In the Pokémon TV series, Misty’s Staryu evolves into Starmie. Staryu and Starmie are Water-type Pokémon associated with Misty’s battling style and with the Cerulean Gym’s aquatic identity.
Misty uses Staryu during her early Kanto adventures, although the Pokémon’s lack of a face means it often communicates through movement rather than expression. After evolving, Starmie becomes a powerful member of Misty’s team and appears in Gym battles and other contests.
Staryu evolves into Starmie when exposed to a Water Stone in the Pokémon game mechanics. The anime’s broader continuity includes many evolution moments, but the species relationship remains the same: Starmie is the evolved form of Staryu.
Staraptor, Lumineon, and Clamperl are different Water-related or aquatic Pokémon, not the evolution of Misty’s Staryu. Misty also owns other Water Pokémon, including Psyduck and Poliwag.