Anableps is the four-eyed fish genus, in its own family within the livebearing toothcarps. The three species in the atlas run large for the group at 12–13.5 in and share the genus's signature trait: each eye is divided by a band of tissue into an upper aerial lens and a lower aquatic lens, letting the fish cruise the surface film watching for insects above the waterline while still scanning for threats below it. They live in brackish coastal waters, mangrove-lined estuaries, and lower river reaches on both sides of Central and South America - the atlas records Anableps anableps and A. microlepis along the Atlantic coast across Guyana, Suriname, French Guiana, Trinidad and Tobago, Venezuela, and Brazil, and the Pacific-coast A. dowii in Guatemala and El Salvador.
All three species are assessed as Least Concern, and the genus is kept mostly by specialist and public aquarists rather than casual hobbyists, since a proper setup needs brackish water, a long tank with plenty of surface area, and enough length to accommodate a genuinely large surface-swimming fish. The real hook for anyone who keeps them is the breeding biology: Anableps are livebearers with a laterally asymmetric gonopodium, so each male and female is effectively right-handed or left-handed, and only opposite-handed pairs can mate successfully - one of the more unusual reproductive quirks in the fish world.