Seaking is a primarily orange-and-white, fishlike Pokémon. It has round, dark eyes, prominent pink lips, two small fangs, and a cream-colored horn in the center of its forehead. A female will have a smaller horn than a male. Most of its body is orange with a patch of white under its mouth and along its underside. There are several black markings on its body: two thick lines under each eye, a large wavy patch on its back, and several speckles near its tail. It has billowing pectoral fins and a pair of tail fins shaped like butterfly wings, all of which are white speckled with black. However, its dorsal fin is pure white and rigid.
Seaking is a very powerful swimmer that is found in rivers and streams. It can swim not only against a river's current, but up waterfalls as well. In the autumn spawning season, it grows fatter and more vibrant. It travels upriver where male Seaking engage in elaborate dances to court females. The female would go for the Seaking with the most graceful dance.
Seaking uses its powerful horn to bore holes in riverbed boulders in order to shelter its Eggs from water currents. A mated pair take turns patrolling around their new nest for roughly a month and defend it with their lives. There are two different groups of Trainers who are obsessed with Seaking's horns or dorsal fins. However, the groups cannot get along with each other. In the past, Waterfall was its signature move.
The Sensational Sisters own a Seaking, which first appeared in The Misty Mermaid. It reappeared in Cerulean Blues and in a fantasy in Alola, Alola!.
In Hook, Line, and Stinker, multiple Seaking were the focus of a local fishing competition. Ash and Misty both hooked a Seaking each.
In The Great Eight Fate!, Juan used a Seaking in a Gym battle against Ash. It was able to block Pikachu's Electric attacks with Horn Drill and send them back at its opponent. Pikachu and Corphish eventually took Seaking down, but not before it defeated Snorunt.
In Pikachu's Vacation, a Seaking was at the Pokémon Theme Park.
In Round One - Begin!, a Trainer's Seaking competed in the Indigo League Conference.
In Pikachu Re-Volts, a Seaking fell under the control of Cassidy and Butch via their Drowzee at Mandarin Island North.
A Seaking appeared in Misty's fantasy in Bye Bye Psyduck.
In The Power of One, multiple Seaking sensed the disturbance caused by Lawrence III.
A wild Seaking appeared in Pikachu's Rescue Adventure.
In Slowking's Day, a Seaking was living in the ocean surrounding Shamouti Island.
A Seaking appeared in a fantasy in The Totodile Duel.
In The Joy of Water Pokémon, a Seaking was living in Lake Lucid.
In Octillery The Outcast, Misty's Poliwhirl went up against a Trainer's Seaking during a qualifying match of the Whirl Cup and won. It reappeared in the following episode.
Multiple Seaking appeared in the opening intro of Celebi: The Voice of the Forest, which was reused for Pokémon Heroes: Latios & Latias.
In Enlighten Up!, a Seaking resided in Lake Slowpoke.
In Putting the Air Back in Aerodactyl!, Tracey observed and sketched three Seaking as they swam in a lake.
In Pokémon Ranger and the Temple of the Sea, The Marina Group used multiple Goldeen for their Marina Underwater Pokémon Show. They reappeared in a montage in The Rise of Darkrai, which highlighted the preceding nine movies.
Multiple Seaking appeared in Kalos, Where Dreams and Adventures Begin!.
Multiple Seaking appeared in Diancie and the Cocoon of Destruction.
A Performer's Seaking appeared in a video in Performing with Fiery Charm!.
In Alola, Kanto!, a wild Seaking was at Professor Oak's Laboratory.
In Dewpider Ascending!, a wild Seaking swam along a river and passed a school of Goldeen.
In Securing the Future!, a Seaking joined the rest of Alola in showering Necrozma with light so it could return to its normal form.
A Seaking appeared in Pikachu's Exciting Adventure!.
In The Cuteness Quotient!, a Seaking appeared under the ownership of Marin. It competed with her in the Friendship Festival. Another Seaking was featured on the poster for the competition. Marin's Seaking reappeared in On Land, In the Sea, and to the Future!, where it competed in the Kids Marine Athletic Race.
||Seaking, the Goldfish Pokémon. Seaking is the evolved form of Goldeen. Its sharp, drill-like horn is capable of crushing even stone.
- In the Pokémon Red and Blue beta, Seaking's prototype name was "Neptune", after the god of the sea in Roman mythology.
- Seaking and Goldeen are the only Pokémon that can learn Waterfall through leveling up.
- Seaking's number in the Sinnoh Pokédex and the Johto Pokédex are the same: 079.
- In Gold, Silver, and Crystal Versions, it appears that Seaking was originally set to learn Supersonic as one of its three starting moves. However, the game programmers made an error and filled the third data slot with Tail Whip, so Seaking ended up with two starting moves instead.
Seaking seems to be based on a goldfish, specifically the ryukin and oranda breeds due to its plump body and billowing tail. Its colorful scales resemble the azuma nishiki and shubunkin goldfish breeds as well as the taishō sanshoku and shōwa sanshoku koi fish breeds. Its behavior is reminiscent of the sockeye salmon, whose bodies flush red as they swim upstream and climb waterfalls during their breeding season. Its horn may be a reference to Matsya, a giant horned fish that is one of the avatars assumed by the Hindu deity Vishnu.
Seaking may be a combination of sea and king (as a compliment to queen in Goldeen), and possibly a corruption of seeking (referring to how it seeks out mates and breeding grounds).
Azumao may be derived from 東錦 azuma nishiki (a variety of goldfish) and 王 ou (king) . Taken literally, it means 東王 azuma-ō (east king).