Goldeen is often overlooked because of its all-around average base stats. However, when Rain Dance is set up, Goldeen can become a very strong sweeper. With Megahorn exclusive to it among Rain Dance sweepers, Goldeen can kill Snover, one of Rain Dance's biggest nemeses. With its decent bulk, Goldeen can also set up Rain Dance for itself and its teammates. For these reasons, Goldeen is a valuable addition to any Rain Dance team.
This set abuses Goldeen's ability, Swift Swim, as well as its advantages over other Rain Dance sweepers in Megahorn, Psybeam, and its greater bulk.
Rain-boosted Waterfall hits like a truck, being able to OHKO common threats in Little Cup, such as Gligar and Gastly. Return provides perfect neutral coverage with Waterfall while hitting Water-type resisters, such as Mantyke. Megahorn is the crux of the set, OHKOing Snover, who normally stops Rain Dance teams cold with Snow Warning. It also OHKOes Carvanha and has a chance to OHKO Wynaut after Stealth Rock damage. Rain Dance allows Goldeen to set itself and its teammates up. Psybeam OHKOes Croagunk, another bane of Rain Dance teams. Be warned, however, that Croagunk's vast range of priority attacks will either cripple or outright KO Goldeen.Team Options & Additional Comments >>>
Goldeen has little utility outside of sweeping in rain. A Scarf set with Megahorn could be usable, reaching 17 Attack and 24 Speed. However, it lacks power without a rain-boosted Waterfall; Buizel generally does a better job. Agility could be used over Rain Dance, but Waterfall again lacks the power required to sweep. Finally, Aqua Tail could be used for the slight power boost over Waterfall, but the 90% accuracy could occasionally be a letdown.
Checks and Counters
Goldeen needs rain to sweep effectively. Therefore, with rain removed, Goldeen becomes much less of a threat. However, the two weather changers in Little Cup, Snover and Hippopotas, are threatened by Megahorn and Waterfall, respectively. With this taken into account, Snover and Hippopotas are not effective counters to Goldeen.
Waterfall cannot OHKO Munchlax unless it switches into Stealth Rock and Goldeen rolls maximum damage with Life Orb under rain. Munchlax can then do massive damage back with Return. The same thing applies to Chinchou and Mantyke, who are only hit by Return and can OHKO or 2HKO back with Thunderbolt and Hidden Power, respectively. Finally, Croagunk can take down Goldeen with priority attacks. It must watch out for Psybeam, however.