Chillquarium

Chillquarium is a game about the part of fishkeeping that is actually fun: the tank gets prettier while you do nothing in particular. You buy fish, they grow in real time, you sell the surplus for profit or keep them for ticket income, and every so often you open a booster pack and find out whether today is the day you get the ultra-rare colour variant. Ben Reber released it on Steam in September 2023 at a modest price, often discounted.

What the loop feels like

You buy a fish, it grows while you are away, and you sell it for profit. The real-time growth loop is genuinely idle: fish mature while the game is closed, so the correct amount of attention is roughly one visit a day, which makes it the rare collection game that respects a commute. That's Chillquarium.

You tear open a booster pack, the rare drop shimmers, and the aquarium gets one tank prettier. The audience rates it very positively, and the reason is visible in the tank: the genre tag is Casual and Simulation, but the honest description is a collection game wearing an idle game's clothes. That's Chillquarium.

The systems doing the work

The named systems are idle progression through real-time fish growth, an economy of selling surplus and collecting ticket income, and the collection layer: a large fish roster with rare and ultra-rare colour variants that is the actual hook. This is booster-pack gacha for people who would rather look at a calm aquarium than a slot machine. Feeding frenzies, day-night cycles and customisable aquariums give the tank enough life that leaving it running feels like owning something, not operating something.

Where it stumbles

The rarity chase is the long game, and it is a long one: completionists report dozens of hours hunting the ultra-rares, and the pack RNG can dry up for stretches. Players wanting active management will find the correct move is usually to leave the tank alone, and there is no real strategy layer beneath the buying and selling.

Playing it today

Live on Steam for Windows, with Achievements, Cloud and Stats, frequently discounted, and Steam-only at check. If the second-monitor comfort appeal is the draw, Rusty's Retirement is the catalogue's other great background companion.

The verdict

Exactly what it says on the tin: a chill aquarium. The gacha pull is gentle, the fish are lovely, and your tank keeps earning while you sleep. A perfect second-monitor idle for people who find farming games too much like farming.