Games like Lofi aquarium
Games like Lofi aquarium include Chillquarium, Spirit City: Lofi Sessions, Cookie Clicker, Joyquarium, and Cast n Chill. We matched them by the tags players give Lofi aquarium on Steam (Creature Collector, Idler, Collectathon, Music, and Automation): closest matches first, and among equally close ones the better-known games.

Chillquarium
Shared: Creature Collector · Collectathon · Idler

Spirit City: Lofi Sessions
Shared: Creature Collector · Cozy · Idler

Cookie Clicker
Shared: Idler · Collectathon · Casual

Joyquarium
Shared: Creature Collector · Idler · Economy

Cast n Chill
Shared: Idler · Creature Collector · Relaxing

Tiny Aquarium: Social Fishkeeping
Shared: Creature Collector · Collectathon · Idler

Keep on Mining!
Shared: Idler · Relaxing · Casual

Mini Cozy Room: Lo-Fi
Shared: Idler · Music · Cozy

Tiny Pasture
Shared: Idler · Creature Collector · Cute

Ithya: Magic Studies
Shared: Idler · Cozy · Music

Fortune Mill
Shared: Idler · Automation · Economy

Ropuka's Idle Island
Shared: Idler · Cozy · Relaxing

Slime Rancher 2
Shared: Creature Collector · Relaxing · Cute

Bugtopia
Shared: Idler · Collectathon · Creature Collector

Plantera
Shared: Idler · Collectathon · Automation

Kind Words (lo fi chill beats to write to)
Shared: Cozy · Relaxing · Music

Cornerpond
Shared: Idler · Creature Collector · Relaxing

Fish to Dish: Idle Sushi
Shared: Idler · Creature Collector · Collectathon

Chonkers
Shared: Creature Collector · Idler · Cozy

Lil Gator Game
Shared: Cozy · Relaxing · Casual

Rusty's Retirement
Shared: Idler · Automation · Relaxing

Incredicer
Shared: Idler · Casual · Relaxing

Placid Plastic Duck Simulator
Shared: Collectathon · Relaxing · Cute

Plantera 2: Golden Acorn
Shared: Idler · Collectathon · Automation