Puntius crescentus, commonly known as the moon tetra, is a species of cyprinid fish native to the Ganges River system in India and Bangladesh. The species belongs to the genus Puntius and is found in many of the larger rivers, flood plains and other lowland habitats. It is one of the few members of the genus to be widely traded in the aquarium trade. The moon tetra is a small fish, reaching a maximum length of around 4.5 cm in total length. It is a colourful fish, with a greenish to yellow body, marbled with black and grey spots. Its tail is red, with a white crescent-shaped spot near its base. Its dorsal fin carries blue and red stripes and the ventral fins are yellow. In its native range, the moon tetra is found in shallow, slow-moving waters, such as canals, ditches, and swamps. Its diet consists of small aquatic invertebrates and detritus, though it may also feed on small land insects that fall into the water. In the aquarium, the moon tetra will thrive on a variety of flake and pellet foods, supplemented with live or frozen foods. The moon tetra is an active, peaceful species that makes an excellent addition to the community aquarium. It tends to do best in schools of six or more, and it should be housed in an aquarium with plenty of well planted open swimming areas. It prefers slightly acidic or neutral water with a pH between 6.0 and 7.0, although it is tolerant of a wider range of pH levels. Breeding is easy and may occur in an aquarium setting once levels of nitrates and nitrites remain low.