Nannostomus

Nannostomus is a genus of freshwater fish commonly known as hatchetfish or pencilfish, belonging to the family Lebiasinidae. These small, slender characins are native to the Amazon and Orinoco river basins in South America. They are popular in the aquarium trade due to their attractive coloration and peaceful disposition.

The genus Nannostomus is characterized by its elongated, torpedo-shaped body, with the mouth positioned at the tip of the snout. Many species exhibit striking patterns of stripes, spots, or other markings, which can vary in intensity and appearance. Their fins are generally small, and their overall appearance has led to the common names hatchetfish and pencilfish.

Nannostomus species are typically small, with most adults reaching only a few centimeters in length. They are omnivorous, feeding on small invertebrates, algae, and detritus in their natural habitat. In aquariums, they readily accept commercial flake and pellet foods, as well as live or frozen options like brine shrimp and daphnia.

These fish are schooling species and thrive in groups of six or more individuals. They prefer well-planted aquariums with soft, acidic to neutral water and moderate to dim lighting. Due to their small size and peaceful nature, they are suitable for community aquariums with other small, non-aggressive fish. Breeding can be achieved in captivity, with most species laying adhesive eggs on plant leaves.