Play Aquarium Online — Free
Fill aquarium tanks with water. The water level in each connected tank section must be consistent, and row/column clues tell you how many cells are filled.
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About Aquarium
Aquarium is a logic puzzle themed around filling fish tanks with water. A grid is divided into tanks (connected regions), and water fills each tank from the bottom up — always leveling horizontally within a tank, just as real water does. Row and column clues tell you how many cells of each line must be filled.
This physical rule — water is always horizontal within a connected tank — is what makes Aquarium distinctive. You’re not deciding independently which cells are filled; you’re choosing the water level for each tank, and that level applies to all cells of the tank at that height simultaneously.
Aquarium requires a blend of arithmetic (counting filled cells per row/column) and spatial reasoning (tracing which cells belong to each tank at each height). The tactile, physics-based logic makes it feel unique among grid-shading puzzles.
The best entry point is always the row and column clues at 0 (mark the entire line as empty) or at maximum (mark the entire line as filled). From there, work out which tanks must be at which water level to satisfy the remaining partial clues.
Frequently asked questions
How does Aquarium work?
The grid is divided into aquarium regions. Water fills each region from the bottom up and must reach the same level in all cells of the same region at the same height. Numbers on rows and columns tell you the total filled cells.