Wooper is a mostly blue, amphibious Pokémon that resembles an upright, armless axolotl. Wooper's head is large compared to its body, and it has small, round, black eyes. It has purple, branching gills on either side of its head; the males have more branches in its gills than the females. Wooper stands on two small, round feet, and it has a large, thick tail. On its belly are dark blue curved markings.
It is implied in the anime that Wooper is a dull-witted Pokémon oblivious to its surroundings. Wooper lives in cold water most of the time. When sleeping, it partially buries itself in the mud at the bottom. It will occasionally leave the water when the air cools in the evening to search for food along the shore. While walking on land, it coats its body with a slimy, toxic film that keeps its skin from dehydrating and insulates against the cold. The film causes a shooting pain if touched barehanded. Arbok is a natural predator of Wooper.
Wooper, the Water Fish Pokémon. Though they prefer to live in cold water, these appealing Pokémon forage for food on land. They are kept warm by a layer of insulating body fluid. Wooper is the pre-evolved form of Quagsire.
Out of all the Pokéfloats, Wooper spends the most time onscreen. It first appears when the scene is on Slowpoke's tail and it then floats past Sudowoodo, Snorlax, Venusaur, and Seel before finally floating away. While its head is small, players can also stand on the gills.
Wooper seems to be based on a larval salamander, which has a flat tail and feathery, external gills. Its Shiny sprite gives it a similar coloration to that of albino, leucistic, and flavistic color mutants, or an axolotl, a species of salamander that keeps its gills and remains in the water for all of its life because it never develops lungs.
Wooper and Upah are derived from wooper looper, a marketing term created in Japan that started a pet salamander raising fad. Wooper loopers are the Japanese term for the axolotl, a species of salamander.