From gonochoric fish to parthenogenetic poeciliids: maximum investments in females

Through this paper we aim to highlight the evolutionary strategy of fish, through which some species try to maximize their investments, directing them to the female sex, which produces offspring. In contrast to females, males only contribute to the production of offspring and can sometimes be dispensable. Among these strategies we mention the hybridogenesis model of the genus Poeciliopsis, the Prussian carp gynogenesis model, and the extreme gynogenetic model of the Amazon molly, a species that is formed almost exclusively from females.