I think we should be able to raise and cultivate fish. Every fish should have a male and female version, and any fish can be raised in a fishery. Fishery can be a building like a rabbit hutch or a chicken coop. Feed your fish worms, or maybe add a few recipes for making fish food from plants/seeds/animals.
Every so often the fish produce roe, and after a while the roe becomes new fish, with quality based on the feed just like a chicken coop or rabbit hutch.