They are hatched from an egg.
the fish are hatched :D
Dory, the fish from nemo, was hatched from an egg.
A newly born or hatched fish is a fry.
eggs
A "Fry" is a recently hatched fish.
fish can live in water because they have gills.
Newly hatched sultan fish are typically small in size and have translucent bodies with underdeveloped fins. They rely on yolk sacs for nutrition initially and are vulnerable to predation in the wild. They often stay close to cover and shoal together for protection.
Dinosaurs hatched from eggs.
Hatched
they are hatched
Newly hatched insects are generally called crawlers.
These life forms and be hatched and born alive, mostly hatched though.