Fish is a versatile mutant that uses his high mobility and ammo income to outrun and outgun enemies. Because of his ability to dodge enemy fire or quickly hide behind cover and his significantly increased ammo income, Fish can be recommended for beginners.
Fish gets more ammo from stationary Ammo Chests, mini pickups and from walking over weapons. Each Mini Ammo Chest gives him 40 bullets, 10 shells, 9 bolts, 8 explosives or 13 energy.
Because of that, Fish will receive more ammo from the Lucky Shot mutation.
He also starts with 120 bullets instead of 96. If he has a Golden Weapon, he will start off with more ammo for it.
Fish rolls in the direction that he is currently moving and can shoot while doing so (he still takes damage while rolling). If Fish is standing still then he will roll in the direction he is aiming.
With water boost, Fish is propelled at rolling speed for as long as the active button is held down. Unlike the normal roll, Fish is able to change direction and stop at any time. This makes Fish highly evasive though not invincible and somewhat hard to control; as such water boost is mainly best for running away from hazards or back towards a safer area. (or coming near hazards to hit them)
While Fish can be a great starting character for the ammo bonus, his roll takes time to master. Note that the roll does not stop when hitting walls and instead bounces outward but the distance is short and it can be used rapidly. The roll is mostly used to dodge enemy projectiles and grab distant pickups before they disappear or just to move faster and hide behind cover. Be careful when using the roll to dodge projectiles, however, as you can roll into more bullets.
Back Muscle - Since Fish gets more ammo from pickups, it's easier for him to use ammo intensive weapons and keep a high ammo capacity with this mutation.
Rabbit Paw - Makes it even easier to stock up large amounts of ammo. Also synergises with Fish's Ultra A, Confiscate.
Lucky Shot - Thanks to his passive, Lucky Shot will give him more ammo than other characters. Also a core component to potent Ranged builds.
Trigger Fingers - With Gun Warrant and a powerful area-of-effect weapon, you can kill a significant percentage of enemies from the start.
Strong Spirit & Rhino Skin - Helps with longevity.
Fish's loading screen tip "Like Kevin Costner", is a reference to the post-apocalyptic movie Waterworld, where Kevin Costner played a mutated human that could breathe underwater.
Fish plays the intro song on his guitar.
It's possible to resist the attraction of portals using Dodge Roll.
The distance of Fish's roll was significantly shortened in update #26 and again in update #38.