Aquarium Techniques

Six techniques solve every Aquarium on PeerPuzzles. Finished lines and flat water do most of the work; too much water and no room take over on bigger grids, where tall tanks run down the columns; every arrangement and what-if finish the hardest. Each page shows its technique on the same 10×10 puzzle from the game, at the moment it’s first needed, so you can follow one solve from page to page.

Hard level 16, the 10×10 every technique page follows. It has 25 tanks, takes 43 steps, and needs all six techniques.

How many of the game’s levels need each one, out of 50 in each track:

Technique	Easy 6×6	Medium 8×8	Hard 10×10
Water lies flat	49	50	50
Finished lines	50	50	50
Too much water	17	41	50
No room	4	21	50
Every arrangement	0	1	42
What if	0	0	39

“Needs” means the hints, which always use the simplest technique that works, used it at least once. For all six in one place, with another worked puzzle, see how to solve Aquarium.

Hard level 16, solved.

Guides

Aquarium: Water Lies FlatThe rule behind every Aquarium move: water fills a tank level, from the bottom. What a water square or a dry square tells you about the rest of its tank, with a real example.
Aquarium: Finished Lines (0s, Full Lines and Just Enough Room)The simplest Aquarium counting: a line with all its water is dry everywhere else, and a line with just enough room is water everywhere else. With a real example.
Aquarium: Too Much WaterIn Aquarium, water never goes in one square alone: it fills its tank's row and everything below. When that would overfill a row or column, the square is dry. With a real example.
Aquarium: No RoomIn Aquarium, a dry square dries everything above it in its tank. When that would leave a row or column without room for its number, the square holds water. With a real example.
Aquarium: Every Arrangement of a LineWhen an Aquarium row or column is crossed by just a few tanks, list the ways their runs can make its number. What's the same in every way is certain. With a real example.
Aquarium: What If? Follow a Choice to a ContradictionWhen no simpler Aquarium technique works, suppose a tank row holds water or stays dry, follow what it forces, and see whether a number can still be met. With a real example.