Given data:
The diameter of cylinder is d=12 cm.
The height of the cylinder is h= 27 cm.
The dimension of the aquarium is V=(35 cm)(40 cm)( 42 cm).
The volume of the cylinder is,

The volume of the aquarium is,

The number of cylinders that can be pour into aquarium is,

Thus, the number of cylinders that can be pour into aquarium is 19.25.