Play Aquarium Puzzle Online Free

Japanese puzzle maker Naoki Inaba invented Aquarium in 2004 under the name Aqua Place. The puzzle divides a grid into outlined tanks and asks you to fill cells with level water while matching row and column totals. It exercises spatial reasoning because gravity controls every region: water cannot float above air inside one tank. Line clues then connect separate regions into one count system. Study the tank floors, identify a forced water level, and start filling an Aquarium puzzle directly in your browser.

1. Read the number beside each row and below each column. Each clue states exactly how many cells in that line contain water. Region borders divide the grid into separate aquariums whose levels may differ.
2. Within one region, fill from the bottom upward. If any cell contains water, every cell of that region on a lower row must also contain water. Cells on the same row inside that region share one state.
3. Start with zero and full line clues. A zero marks every cell in that row or column dry. A clue equal to the line length fills every cell, then gravity may force lower cells in the same regions.
4. Subtract known water cells from each line total and compare the residual with undecided cells. When the numbers match, fill all remaining cells. When the residual reaches zero, mark all remaining cells dry.
5. Finish when all region levels obey gravity and every row and column contains its stated number of water cells. Check region segments on the same horizontal level, since separated-looking cells can belong to one outlined tank.

• Every outlined region represents one aquarium with a single horizontal water surface. Water fills all region cells below that surface and none above it.
• Cells belonging to the same region and the same row must share the same state. You cannot fill one while leaving another dry, even when a bend in the region separates them visually.
• Each row clue equals the number of water cells in that row. Each column clue independently equals the number of water cells in that column.
• Different regions may have different water levels. Gravity applies within each outlined aquarium and does not force equal heights across a shared row.
• All cells receive a final water or dry state. A solution must satisfy both the geometric region rule and every line count at once; neither condition can excuse a mismatch in the other.

• Mark upward consequences of dry cells. If a lower cell in a region is dry, every cell above it in that region must also stay dry. This contrapositive form of the gravity rule often proves more useful than filling downward.
• Group same-level region cells as a unit. When three cells from one tank occupy row 4, they contribute either three water cells or zero at that level. A row residual of one cannot use that group, so mark it dry.
• Use row clues to choose a surface, then confirm it with columns. A region's possible states correspond to a limited set of horizontal levels. Eliminate any level that makes a crossing column exceed its clue or fall short of its residual.
• Compare adjacent line residuals. If two neighboring rows pass through the same regions, the lower row cannot contain fewer water cells contributed by those regions. Differences can expose which separate tank changes level between the rows.
• Delay isolated guesses. Record water, dry, and unknown states, and propagate each forced region level through every occupied row. Most stalls disappear after a complete pass through columns followed by a complete pass through regions.

• Kakurasu: Kakurasu also uses totals at the grid edges, but position weights determine its sums. Aquarium counts cells equally and adds region gravity. The pair shows how similar line clues support different reasoning.
• Shikaku: Shikaku divides a grid into rectangles with fixed areas. Aquarium begins with irregular regions and asks you to locate horizontal water surfaces. Both make region geometry central to each deduction.

• The water rule feels physical and easy to inspect. Once a cell fills, players can follow gravity through its region and see why lower cells must fill too.
• Irregular tanks create varied deductions from plain row and column counts. A wide level may act as a large all-or-nothing group, while a narrow shaft changes one count at a time.
• Each solve alternates local and global reasoning. Region levels answer local questions, while line totals connect distant aquariums and produce satisfying chains across the board.

Play Aquarium online for free with clear region outlines, row totals, and column totals on one screen. Mark water and dry cells as you test each possible surface. The browser removes setup work and lets you correct a state without redrawing the grid. Start on a compact board to practice gravity, then move to a larger puzzle where bent regions and wide levels make every line count matter.

Aquarium combines Naoki Inaba's 2004 Aqua Place idea with direct, physical logic. Fill each region from its floor, keep same-level cells together, and use line residuals to choose among possible surfaces. A forced water cell can settle a tank; a forced dry lower cell can clear everything above it. Begin a puzzle above, inspect the lowest uncertain levels first, and connect each region decision to the row and column totals around the grid.

• Aquarium puzzle history and rules (WPC Unofficial)