Cyematidae

Cyematidae is a small family of deep-sea fishes belonging to the order Anguilliformes, commonly known as deep-sea eels. The family currently contains only two genera, Cyema and Neocyema, with a total of three recognized species. These eels are characterized by their elongated, tadpole-like bodies, with a large head relative to their body size. They possess a distinctive, scoop-shaped mouth and very small, degenerate eyes, adaptations reflecting their life in the aphotic zone of the ocean. Their skin is thin and translucent, often revealing their internal organs.

Cyematids are found in deep waters across tropical and temperate oceans worldwide, typically at depths ranging from 1,000 to 4,000 meters. Their diet is not well-understood, but it is believed to consist of small invertebrates and possibly detritus. Information on their reproductive biology and life cycle is also scarce due to the challenges of studying these elusive creatures in their natural habitat. They are rarely encountered by humans, and their ecological role in the deep-sea environment remains a subject of ongoing research. The taxonomic placement of Cyematidae within Anguilliformes has been consistent, though their evolutionary relationships with other eel families are still being investigated.