Aquarium is a logic puzzle with simple rules and challenging solutions.

The rules of Aquarium are simple:
The puzzle is played on a rectangular grid divided into blocks called "aquariums"
You have to "fill" the aquariums with water up to a certain level or leave it empty.
The water level in each aquarium is one and the same across its full width
The numbers outside the grid show the number of filled cells horizontally and vertically.

Note: there is a "Mass Print" page