Build and Runes
Throw salt at him, this will demoralize him and make him all dried up.
Buying a Quicksilver Sash and using it will drop the fish from his ultimate, allowing you to avoid the shark.
Focus him after he uses Playful/Trickster to enter a fight.
Avoid staying in lane with low health, as Fizz’s Seastone Trident will deal greater damage against lower health targets.
Banshees Veil negates Fizz’s shark. His entire combo is lost when your Banshees is up.
Fizz likes to weave in and out of a fight to wait for his cooldowns, so try to take advantage of the time when he is useless and disrupt him with your front line, while keeping your carries safe to handle his extreme damage.