How to Play Aquarium
Aquarium is a logic puzzle with a physical twist: the grid is cut into tanks, and water obeys gravity. Decide how high each tank is filled so that the row and column counts come out right.
The rules
- Bold lines divide the grid into tanks.
- Each tank is filled with water up to one level: every cell of the tank at that row or below is water, everything above is air.
- So within a tank, the cells of one row are all water or all air, and water never floats above air.
- The number beside a row and under a column is the count of water cells in it.
Playing on kawu
- Tap a cell to fill it with water, tap again for air (×), again to clear.
- A count turns red when its row or column already breaks it; cells turn red when water floats or a tank row is mixed.
- Undo steps back; Hint fixes a wrong cell or settles one from the physics or a full count.
- Sizes 6×6, 8×8 and 10×10; the daily puzzle is an 8×8 shared by everyone.
Then read Aquarium solving tips.
Frequently asked questions
Can water be at different heights in the same tank?
No. A tank has one water level: every cell of the tank at or below that level is wet, every cell above it is air, even if the tank bends around other tanks.
Can a tank be completely empty or completely full?
Yes to both. The counts decide.
Last updated 2026-10-21