Ichthyological terms, not general ones.
Not an official term in genetics, but often used in reference to the founder, or parental, generation in a line of captive-bred organisms. Also used in aquarium literature to refer to wild caught fishes or a pair or group of assumedly unrelated individuals being used for breeding purposes.
Term used in the fields of genetics and selective breeding in reference to the first filial generation, i.e., hybrid offpsring, of a cross between two distinctly different parental lines. Often used in aquarium literature to refer to offspring of F0 parents whether of the same species or not.
Of, relating to or being a generation or the series of generations following the parental (F0) generation.