Forum:Cerulean Gym 2

Electric- and Grass-type attacks work well in this stage. If you have a strong Pikachu/Raichu or Victreebel/Vileplume, use moves such as Electro Ball, Thunderbolt or Giga Drain. Be advised that Thunder, Thunderbolt, Giga Drain, and Solar Beam are all effective TM moves that can be taught to many Pokémon available at this point.

Status moves, such as Sleep Powder and Thunder Wave, may help slow Kyogre down enough for you to get in some extra attacks. Kyogre will use Kyogre's Rest and put himself to sleep, also healing his HP.

One-hit KO moves like Guillotine or Horn Drill will make the level much easier, but your Pokémon must be over level 25 for it to be successful.