Juveniles hang in the top few metres at night with the pectoral fins already spread, years before they can use them.
The adult is the fish everyone has seen from a boat: it builds speed underwater, breaks the surface, and glides on enlarged pectoral fins, beating the lower lobe of the tail against the water to extend the glide. A good one covers two hundred metres in a series of taxiing hops. The gliding is escape behaviour, from tuna and dolphinfish rather than from boats.
Juveniles are the blackwater subject. At a few centimetres the pectoral fins are already enormous relative to the body and are held spread while the fish hovers, which is what makes them photographable at all — they are otherwise nearly transparent. Many species carry barbels on the chin as juveniles, sometimes longer than the fish, and lose them as they grow.
Species-level identification of a juvenile exocoetid from a photograph is not realistic, and this entry does not attempt it. There are around seventy species and the useful characters are fin ray counts.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
