Lebiasinidae

Lebiasinidae is a family of freshwater fish commonly known as characins or tetras, though they are distinct from the true tetras of the family Characidae. This family is found in South America, primarily in the Amazon and Orinoco river basins, as well as in adjacent river systems. Lebiasinids are small to medium-sized fish, typically with a laterally compressed body and a forked tail fin. They exhibit a wide range of coloration, often with iridescent scales or distinct markings.

The diet of lebiasinids varies, with many species being omnivorous, feeding on small invertebrates, insects, and plant matter. Some species are known to be more specialized feeders. They are generally found in slow-moving waters, such as streams, swamps, and the margins of larger rivers, often inhabiting areas with dense vegetation. Reproduction in Lebiasinidae typically involves the laying of eggs, often among aquatic plants. Some species may exhibit parental care, though this is not universal within the family.

The family Lebiasinidae is divided into several genera, including Lebiasina, Nannostomus, and Poecilocharax. Species within these genera can differ significantly in morphology and behavior. For example, the pencilfish genus Nannostomus is well-known in the aquarium trade for its elongated, pencil-like body shape. Other genera, like Lebiasina, may have more typical characin-like bodies. Due to their often vibrant colors and interesting behaviors, several lebiasinid species are popular among aquarists.