In the Middle Ages, it was thought to hatch from barnacles, and thus was considered "fish" and could be eaten on Fridays.

Many fish larvae hatch without fully formed pectoral fins and all hatch without a swim bladder, so similar problems could occur for them.

Every season, even in the goldfish spawning aquatic or in an aquarium, so the goldfish in brown eggs hatch, small grass and even after such points, according to a fish eating fish and string.