The Astronotus (Astronotus ocellatus), also known as the Oscar, is one of the most charismatic and recognizable fish in modern aquaristics. This representative of the cichlid family (Cichlidae) has won the hearts of millions of enthusiasts worldwide, not only due to its impressive appearance but also its remarkable intelligence. Many owners call their pets “water dogs” because Oscars can recognize their owner, beg for food, and even exhibit rudimentary playful behavior. However, keeping such a giant requires aquarists to have in-depth knowledge and a responsible approach to organizing its living space, as mistakes in caring for such a large fish can lead to sad consequences.