Akvarij

Akvarij is a transparent container used to keep aquatic animals and plants in a controlled environment. In Croatian, the term describes both hobby setups and public displays. Aquaria range from small desktop tanks to large installations and can be configured for freshwater, saltwater, or brackish conditions.

Typical components include the tank, stand, lid, filtration, heating for tropical species, and lighting. Substrate such as gravel or sand, along with decorations, create habitat structure and influence water chemistry. Many aquariums use live aquatic plants to aid oxygen production and nutrient balance; others rely on artificial plants.

Aquariums are categorized by water type: freshwater, saltwater (marine), and brackish. Freshwater tanks are most common for beginners. Saltwater tanks, especially reef setups, require more specialized equipment, water chemistry control, and maintenance. Brackish tanks use water with intermediate salinity, often for specific species.

Setting up an aquarium typically involves conditioning water and establishing the nitrogen cycle, where beneficial bacteria convert ammonia to nitrite and then to nitrate. A fishless cycle is commonly recommended before adding fish. After cycling, stock is added gradually while monitoring parameters such as ammonia, nitrite, nitrate, pH, and temperature.

Maintenance includes regular partial water changes, filter cleaning, substrate cleaning, and monitoring for disease and algae. Overfeeding, overstocking, or neglecting water quality can harm inhabitants. Quarantining new animals before introducing them to the main tank is advised to reduce disease risk.