
Assassin · magic (AP) damage
Fizz is a Assassin that deals magic (AP) damage and brings airborne, slow. Some of their lockdown (airborne) ignores tenacity, so you dodge it; you can't cleanse or Merc' through it. Below is Fizz's highest-win-rate build from high-elo games; open the counter-build tool to tune it against your specific enemy team.

Fizz can move through units and takes a flat amount of reduced damage from all sources

Fizz dashes through his target, dealing magic damage and applying on hit effects.

Fizz's attacks bleed his enemies, dealing magic damage over several seconds. Fizz can empower his next attack to deal bonus damage and empower his further attacks for a short time.

Fizz hops into the air, landing gracefully upon his spear and becoming untargetable. From this position, Fizz can either slam the ground or choose to jump again before smashing back down.

Fizz tosses a fish in a direction that attaches to any champion that touches it, slowing the target. After a short delay, a shark erupts from the ground, knocking up the target and knocking any nearby enemies aside. All enemies hit are dealt magic damage and slowed.
R Chum the WatersSlowignores tenacityFROM
E Playful / Trickster
R Chum the WatersHover a crowd-control type to see which ability it comes from.
Domination
Electrocute
Dark Harvest
Hail of Blades
Cheap Shot
Taste of Blood
Sudden Impact
Sixth Sense
Grisly Mementos
Deep Ward
Treasure Hunter
Relentless Hunter
Ultimate Hunter
Sorcery
Summon Aery
Arcane Comet
Deathfire Touch
Axiom Arcanist
Manaflow Band
Nimbus Cloak
Transcendence
Celerity
Absolute Focus
Scorch
Waterwalking
Gathering Storm

Based on 5881 games · 51.4% win rate · challenger+grandmaster+master+emerald-diamond+platinum-emerald · patch 16.18.1.
Precision
Press the Attack
Lethal Tempo
Fleet Footwork
Conqueror
Absorb Life
Triumph
Presence of Mind
Legend: Alacrity
Legend: Haste
Legend: Bloodline
Coup de Grace
Cut Down
Last Stand
Domination
Electrocute
Dark Harvest
Hail of Blades
Cheap Shot
Taste of Blood
Sudden Impact
Sixth Sense
Grisly Mementos
Deep Ward
Treasure Hunter
Relentless Hunter
Ultimate Hunter

Based on 781 games · 50.1% win rate · challenger+grandmaster+master+emerald-diamond+platinum-emerald · patch 16.18.1.
Domination
Electrocute
Dark Harvest
Hail of Blades
Cheap Shot
Taste of Blood
Sudden Impact
Sixth Sense
Grisly Mementos
Deep Ward
Treasure Hunter
Relentless Hunter
Ultimate Hunter
Sorcery
Summon Aery
Arcane Comet
Deathfire Touch
Axiom Arcanist
Manaflow Band
Nimbus Cloak
Transcendence
Celerity
Absolute Focus
Scorch
Waterwalking
Gathering Storm

Based on 204 games · 42.6% win rate · challenger+grandmaster+master+emerald-diamond+platinum-emerald · patch 16.18.1.
Domination
Electrocute
Dark Harvest
Hail of Blades
Cheap Shot
Taste of Blood
Sudden Impact
Sixth Sense
Grisly Mementos
Deep Ward
Treasure Hunter
Relentless Hunter
Ultimate Hunter
Precision
Press the Attack
Lethal Tempo
Fleet Footwork
Conqueror
Absorb Life
Triumph
Presence of Mind
Legend: Alacrity
Legend: Haste
Legend: Bloodline
Coup de Grace
Cut Down
Last Stand

Based on 48 games · 37.5% win rate · challenger+grandmaster+master+emerald-diamond+platinum-emerald · patch 16.18.1.