Amblyopsis

Amblyopsis is a genus of ray-finned fish belonging to the family Amblyopsidae. The most well-known species in this genus is Amblyopsis spelaea, commonly known as the Northern cavefish. This species is native to subterranean waters of the eastern United States, primarily found in caves in parts of Kentucky and Indiana. Amblyopsis spelaea is characterized by its lack of pigmentation and reduced or absent eyes, adaptations typical of obligate troglobites, meaning they live their entire lives in caves and are dependent on this environment.

The Northern cavefish is a small, slender fish, typically reaching lengths of around 4 to 6 centimeters. They possess a pale, almost translucent body and have sensory pores on their head that help them detect prey in the darkness. Their diet consists mainly of small invertebrates, such as crustaceans and aquatic insects, that also inhabit the cave ecosystem. Reproduction in Amblyopsis spelaea involves internal fertilization, and females carry their eggs internally until they hatch. The young are then released as fully developed larvae, capable of independent survival.

The genus Amblyopsis is named from the Greek words "amblys" meaning "blunt" or "dull" and "opsis" meaning "appearance" or "sight," referring to the reduced eyesight of these cave-dwelling fish. Conservation efforts are important for Amblyopsis species due to their restricted habitats and vulnerability to environmental changes, such as water pollution or alterations to cave hydrology.