Tap Tap Fish - AbyssRium

Every so often an idle game admits it is a lava lamp. Tap Tap Fish - AbyssRium is SangHeon Kim's 2016 offering, a one-developer deep-sea zen garden that became a quiet phenomenon: a lonely corallite at the bottom of the ocean, calming music, and a fish tank that grows one tap at a time. It sold itself as stress relief, and for a while it was exactly that.

What the loop feels like

You tap the corallite and Vitality accumulates in fat little bubbles. Spend some on a coral, and the reef generates Vitality on its own; spend some on a fish, and every single fish you add doubles the output of everything you own. A manta ray drifts in, then a dolphin, then a humpback whale the size of the screen. You put your phone down and the aquarium hums. That's AbyssRium.

The skills are the active layer. Volcano auto-taps the reef in bursts, Delicious Food multiplies your tap income, and Song of the Moon multiplies all production for a stretch. Sync them together when the letter-suffix numbers get steep, and the wall comes down. That's AbyssRium.

How it actually works

Under the serenity sits textbook incremental math. The Lonely Corallite anchors the screen, producing base Vitality and hosting your growing ecosystem. Corals raise passive generation per second, and upgrading them in 25-level blocks triggers multiplicative jumps. Fish are the signature mechanic: each individual fish purchased doubles overall Vitality production from all sources, making collection genuinely economic rather than cosmetic. Vitality scales exponentially into letter suffixes, progression periodically hits a deliberate wall where coral levels outprice your income and patience does the rest, and unlock thresholds on fish counts open higher-tier corals and hidden species. Pearls, the premium currency, buy permanent stat-boosting statues and cooldown reductions.

Where it stumbles

The community's long view is that the game grew away from itself. What launched as a stripped-back, atmospheric tap simulator evolved into a heavy event-driven ecosystem, with bingo boards, crafting materials, secondary currencies and theme updates piling onto the original coral rock until the UI cluttered and the bugs crept in. Finishing time-limited events without paying, players report, can mean watching ads by the hundreds, a grind the community has nicknamed the ad simulator. The developer eventually answered with AbyssRium Classic, a stripped-back relaunch that quietly concedes the point, and the modern version's monetisation remains the core complaint across the fanbase.

Playing it today

Free on the App Store with in-app purchases, still maintained nearly a decade on, with a reasonably positive rating on a smaller recent review base. Get it on the App Store for iOS, or look at the developer's newer Classic edition if the event machinery puts you off. For aquarium idling with more satire, our Behind Glass entry filters the same fish through a management lens, and Cookie Clicker is where all these bubbles started.

The verdict

Still the most beautiful spreadsheet on mobile, and at its calm core a genuinely soothing tap game. Play it slow and ignore the event banners, and it remains what it promised in 2016.