Trigonectes

Trigonectes is a genus of fish in the family Rivulidae. These annual killifish are endemic to the Paraguay River, upper Madeira (Beni, Guaporé and Mamoré) and Tocantins basins in far northern Argentina, Bolivia, central Brazil and western Paraguay. They inhabit seasonal swamps, pools and similar habitats in open regions (for example, savanna). Once the water disappears, the adults die, but the eggs that have been laid in the bottom remain, only hatching after several months (up to a year) when the water returns.