The Karlovac Freshwater Aquarium is situated on the right bank of the Korana River. The structure is dug into the ground, and its exterior sides covered in an earthen embankment. The inspiration for the architecture is the historical town centre: the Karlovac star-shaped town, surrounded by earthen defensive embankments.

The aquarium facilities surround this square, without countering the natural appearance of the Korana valley.

The aquarium exhibition areas present an overview of the flora and fauna of Croatia’s rivers and their ecosystems, the geological past, and the traditional culture and history of the Karlovac area that lies on four rivers. The aquarium shows an overview of the course of karst rivers – the river flora, fauna and its biodiversity.

At the end of the exhibition area, the staircase and elevator return visitors to the entrance gallery via the souvenir shop. In the centre of the building is a laboratory for the analysis of technological water parameters, a scientific , and fish acclimatisation room.