Games like Fish Game
Games like Fish Game include PC Building Simulator, House Flipper, My Dream Setup, WorldBox - God Simulator, and Megaquarium. We matched them by the tags players give Fish Game on Steam (Immersive Sim, Creature Collector, Sandbox, Building, and Idler): closest matches first, and among equally close ones the better-known games.

PC Building Simulator
Shared: Immersive Sim · Building · Sandbox

House Flipper
Shared: Building · Sandbox · Design & Illustration

My Dream Setup
Shared: Building · Sandbox · Design & Illustration

WorldBox - God Simulator
Shared: Sandbox · Building · God Game

Megaquarium
Shared: Sandbox · Building · Creature Collector

The Sims™ 4
Shared: Building · Sandbox · Life Sim

The Tenants
Shared: Building · Immersive Sim · Design & Illustration

Tiny Glade
Shared: Building · Sandbox · Design & Illustration

Stardew Valley
Shared: Sandbox · Life Sim · Building

Aquarist
Shared: Sandbox · Fishing · Education

King of Retail
Shared: Immersive Sim · Sandbox · Building

The Sims™ 2 Legacy Collection
Shared: Sandbox · Building · Immersive Sim

Home Design 3D
Shared: Immersive Sim · Sandbox · Building

WEBFISHING
Shared: Creature Collector · Fishing · Casual

House Builder
Shared: Building · Immersive Sim · Education

Paralives
Shared: Building · Life Sim · Sandbox

Garry's Mod
Shared: Sandbox · Building · Casual

Kerbal Space Program
Shared: Sandbox · Building · Education

SimCity™ 4 Deluxe Edition
Shared: Immersive Sim · Building · Sandbox

Supermarket Simulator
Shared: Immersive Sim · Building · Simulation

MakeRoom
Shared: Immersive Sim · Sandbox · Building

Builder Simulator
Shared: Building · Sandbox · Immersive Sim

Two Point Museum
Shared: Building · Sandbox · Simulation

Stormworks: Build and Rescue
Shared: Sandbox · Building · Immersive Sim