Big eyes – Priacanthidae – is a family of fish that can easily be distinguished due to their large eyes and rough scales. The species is a carnivore that hunts at night and typically features bright colors that seem to be well-adapted to their way of life. There are a total of 19 species of big eyes belonging to the Pricanthidae family, most of which are capable of reaching lengths of up to 30-50 cm on average – although the upper limit is far less frequently reached. Notably, these fish tend to live near rocks or coral reef formations, where they are rarely spotted near the surface. Instead, they prefer deeper, darker and cooler waters, where normal scuba diving gear would be useless.
Unlike many of their counterparts on the reef, big eyes (Priacanthidae) have been around for up to 40-50 million years. Fossils of the species were discovered dating back to the lower Tertiary period, and the evolutionary differences between the big eyes and their ancestors are not too imposing. While some species can be found closer than 100 meters of the surface, near reef constructions, species like the Cookeolus Japonicus (or longfinned bullseye) tend to stay at around 200 meters below the surface, sometimes going as deep as 400 meters. You can find most species throughout many tropical and subtropical waters from around the world, including the Pacific Ocean, off the coasts of Peru and Mexico, as well as Canada, the Red Sea, the Indian Ocean and the South Atlantic Ocean.
There are specific feeding times preferred by big eyes, mostly after dusk. These nocturnal carnivores prefer live meat and are not afraid to go hunting in the deepest reaches of the ocean to find it. The smaller big eyes species tend to prefer smaller shrimp and invertebrates, as well as worms; and some have even been known to have a taste for terrestrial or freshwater worms. Larger species tend to prefer small fish and ghost fish.
Big eyes are elusive, solitary and difficult to spot; however, their reproduction cycles have been observed and studied. While they are not particularly territorial, the fish do prefer individual dark caves they can turn into dwelling places. Like many other species, bigeye species are not overly protective of their young. Once they spawn, they are given total freedom by their parents, and are already known to be capable of fending for themselves. In case of most big eyes, Priacanthidae experts consider that their ability to thrive in deeper waters protect their young from most surface-dwelling predators.