How the fish do they sex and lay eggs?

Fish reproduction varies by species, but most commonly, they are either oviparous (laying eggs) or viviparous (giving birth to live young). In oviparous species, females release eggs into the water, where males fertilize them externally. Some species exhibit unique behaviors, such as nest building or guarding, to protect the eggs. In contrast, viviparous fish, like some sharks and guppies, nurture their young internally until they are ready to be born.