Aldrovandia gracilis

<em>Aldrovandia gracilis</em> is a deep-sea saltwater fish of the family Halosauridae, the halosaurs—an ancient group of elongate, eel-like fishes adapted to life on the deep ocean floor. Growing to approximately 55 cm in length, this species has been recorded at depths of 460 to 2,560 meters, spanning the upper bathypelagic to the abyssal zone. Halosaurs are characterized by their rostrum projecting beyond the mouth, a heterocercal-like tail, and rows of large scales along the lateral line. They are benthic or benthopelagic predators, feeding on invertebrates and organic matter close to the seafloor. The genus <em>Aldrovandia</em> is distributed in the deep Atlantic, Indian, and Pacific Oceans. Details of habitat and range for this species remain limited in the ichthyological literature. <em>A. gracilis</em> has not been evaluated by the IUCN. The enormous depth range recorded for this species may reflect either genuine ecological flexibility or uncertainty in depth assignments across different collection events. Halosaurs are relatively poorly known due to the challenges of sampling in deep-ocean environments.