The Pacific four-eyed fish (''Anableps dowei)'' is a species of

four-eyed fish The four-eyed fishes are a genus, ''Anableps'', of fishes in the family Anablepidae. They have eyes raised above the top of the head and divided in two different parts, so that they can see below and above the water surface at the same time. The ...

native to the coastal waters on the Pacific side of southern

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Nicaragua Nicaragua, officially the Republic of Nicaragua, is the geographically largest Sovereign state, country in Central America, comprising . With a population of 7,142,529 as of 2024, it is the third-most populous country in Central America aft ...

. This fish is gregarious and inhabits

mangrove swamp Mangrove forests, also called mangrove swamps, mangrove thickets or mangals, are productive wetlands that occur in coastal intertidal zones. Mangrove forests grow mainly at tropical and subtropical latitudes because mangrove trees cannot withs ...

s, tidal mudflats, and other coastal

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

ecosystems. During low tide, they will crawl onto shore to eat

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

and other organic matter. This species has female biased

sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

, with males growing to TL while females can grow up to TL. The male also has a prominent

gonopodium Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

used to impregnate females during mating. As with other members of Anablepinae, this species is livebearing and has left or right leaning genitals to prevent

inbreeding Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely genetic distance, related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genet ...

. The name "four-eyed fish" comes from how the eyes of the fish are split into two lobes horizontally, each with its own pupil and vision. This allows the fish to see above and below the water at the same time..Aiding in predator detection and prey location. Additionally, the fish has specialized muscles enabling each eye to adjust its focus independently, further enhancing its ability to adapt to both aerial and aquatic environments.

References

{{Taxonbar, from=Q947767 Anablepidae Viviparous fish Fish of Central America Freshwater fish of Central America Euryhaline fish of Nicaragua Cyprinodontiformes Taxa named by Theodore Gill category:Fish described in 1861