Games like Fish
Games like Fish include Cell to Singularity - Evolution Never Ends, Cookie Clicker, Crush Crush, Chair Simulator, and The Murder of Sonic the Hedgehog. We matched them by the tags players give Fish on Steam (Free to Play, Casual, Psychological Horror, Incremental, and Simulation): closest matches first, and among equally close ones the better-known games.

Cell to Singularity - Evolution Never Ends
Shared: Free to Play · Incremental · Simulation

Cookie Clicker
Shared: Incremental · Casual · Horror

Crush Crush
Shared: Free to Play · Incremental · Hentai

Chair Simulator
Shared: Psychological Horror · Hentai · Free to Play

The Murder of Sonic the Hedgehog
Shared: Free to Play · Casual · Point & Click

Ultimate Custom Night
Shared: Free to Play · Horror · Singleplayer

Horripilant
Shared: Incremental · Casual · Horror

Digseum
Shared: Casual · Incremental · Simulation

Poppy Playtime
Shared: Free to Play · Horror · Psychological Horror

Nodebuster
Shared: Casual · Incremental · Simulation

That's not my Neighbor
Shared: Casual · Horror · Point & Click

Idle Champions of the Forgotten Realms
Shared: Free to Play · Incremental · Idler

MiSide
Shared: Psychological Horror · Horror · Singleplayer

The Sims™ 4
Shared: Free to Play · Simulation · Casual

Click the Button
Shared: Casual · Incremental · Simulation

IdleOn - The Incremental MMO
Shared: Free to Play · Incremental · Idler

Dark Deception
Shared: Free to Play · Horror · Psychological Horror

Drug Dealer Simulator: Free Sample
Shared: Free to Play · Casual · Simulation

Shelldiver
Shared: Casual · Incremental · Simulation

Five Nights at Freddy's
Shared: Horror · Psychological Horror · Singleplayer

An alt girl for skoof
Shared: Psychological Horror · Casual · Hentai

DISTRAINT 2
Shared: Psychological Horror · Horror · Singleplayer

A Game About Feeding A Black Hole
Shared: Casual · Incremental · Simulation

Click and Conquer
Shared: Casual · Incremental · Simulation