How are flying fish born and what they called?

Flying fish give birth to live young that are tiny and transparent. The young fish float and then swim in the open ocean just under the surface so they look very different to adult flying fish. They lack pelvic fins (the lowest ones behind the anal fin). After some growth some develop pelvic fins and turn into halfbeaks, then finally others keep growing longer pectoral fins which become wings enabling them to glide like flying fish as we know them!

What are the young fish called?

The scientific name for a baby flying fish is "fry".