Choose six, moveset canges are not going to be needed. Mono-water battle.
Blastoise: Mirror Coat, Hydro Pump, Ice Beam, Flash Cannon
Golduck: Dig, Light Screen, Hydro Pump, Psychic
Kingler: Hyper Beam, Giga Impact, Crabhammer, Flail
Seaking: Waterfall, Horn Drill, Megahorn, Agility
Feraligatr: Bite, Hydro Pump, Superpower, Aqua Tail
Azumarill: Tail Whip, Aqua Tail, Iron Tail, Hydro Pump
Politoed: Perish Song, Hyper Voice, Whirlpool, Bounce
Octillery: Sludge Bomb, Flamethrower, Octazooka, Energy Ball
Suicune: Gust, Roar, Tailwind, Blizzard
Wailord: Water Spout, Dive, Splash, Hydro Pump
Milotic: Aqua Ring, Safeguard, Attract, Hydro Pump
Huntail: Hyper Beam, Giga Impact, Bite, Hydro Pump
Gorebyss: Psychic, Hydro Pump, Aqua Tail, Dive
Luvdisc: Sweet Kiss, Attract, Safequard, Flail
Kyogre: Water Spout, Rest, Sleep Talk, Ice Beam
Floatzel: Razor Wind, Crunch, Ice Fang, Giga Impact
Lumineon: Silver Wind, Bounce, U-Turn, Whirlpool
Manaphy: Water Pulse, Bubblebeam, Heart Swap, Rain Dance
Poliwrath: Mind Reader, Psychic, Dynamicpunch, Submission
Tentacruel: Toxic Spikes, Hydro Pump, Wrap, Poison Sting
Slowbro: Brick Break, Ice Punch, Psychic, Psych Up
Dewgong: Ice Beam, Safeguard, Aqua Tail, Dive
Cloyster: Spike Cannon, Spikes, Protect, Aurora Beam
Starmie: Psychic, Rapid Spin, Recover, Swift
Gyarados: Hyper Beam, Dragon Rage, Hydro Pump, Bounce
Lapras: Surf, Sing, Psychic, Dragon Pulse
Lanturn: Flash, Thunder Wave, Confuse Ray, Hyper Beam
Quagsire: Water Gun, Muddy Water, Haxe, Mist
Slowking: Nasty Plot, Trump Card, Slack Off, Psychic
Qwilfish: Surf, Spikes, Toxic Spikes, Explosion
Corsola: Already given in Rock question.
Mantine: Psybeam, Bullet Seed, Signal Beam, Confuse Ray
Kingdra: Hydro Pump, Yawn, Twister, Waterfall
Swampert: Hammer Arm, Earthquake, Strength, Waterfall
Ludicolo: Nature Power, Mega Drain, Giga Impact, Hyper Beam
Pelipper: Steel Wing, Surf, Swallow, Stockpile
Sharpedo: Same as in Dark type question
Whiscash: Earthquake, Thrash, Spark, Fissure
Crawdaunt: Same as in dark question.
Relicanth: Same as in Rock question.
Empoleon: Hyper Beam, Steel Wing, Hydro Cannon, Bubblebeam
Gastrodon: Recover, Rain Dance, Body Slam, Muddy Water
Palkia: Aura Sphere, Spacial Rend, Hyper Beam, Hydro Pump
Omastar: Same as in rock question
Kabutops: Same as in rock question
Walrein: Ice Ball, Blizzard, Sheer Cold, Ice Fang
Bibarel: Curse, Superpower, Take Down, Super Fang