Vic Bragg was a swimming champion before turning to crime, before he fell in with Dr. Krill, the brilliant medical doctor and marine biologist who had also turned to a life of crime for some unknown reasons. Dr. Krill had been studying Aquaman's powers and crime-fighting methods, and had hypothesized that the only way for a person to commit crimes on the sea is if one could escape into the air afterwards, where Aquaman would not be able to follow.
After coming to this conclusion, Dr. Krill surgically altered Bragg making him not only just amphibious, but able to take to the air for short periods of time with the aid of a special costume. After several months of recovery and training, Bragg began his career as the Human Flying Fish. Initially, Aquaman was indeed stymied by the Human Flying Fish's ability to escape into the air for a time, but he soon came up with clever ways to counter that advantage, and eventually captured both criminals.
Post Crisis Fish
The Human Flying Fish that appeared in Aquaman, The Sword Of Atlantis #54 is also called Bragg (by Krusivax, his employer) and is revealed to be a seasoned criminal, which implies is the same Bragg as before Crisis on Infinite Earths. He was a hired mercenary and security chief for the Tri-dent base. He was able to beat Arthur Joseph Curry (the second Aquaman) on his own and later showed some consciousness, when he decided to abandon the villains after finding out that their true plans could kill countless people.
In Justice League #18 during a meeting at the Justice League headquarters, Aquaman and Vixen mention how they had previously apprehended a super villain called "The Flying Fish".
Powers and Abilities
Human Flying Fish is amphibious and super humanly fast due to the medical experiment he underwent, and able to fly with help from his costume.
Bragg is able to fly at high speeds thanks to the special winged suit he is wearing. He is very precise at flying able to snatch bird while they are flying or board a flying plane.
Superhuman Swimming Speed
Bragg is able to swim at speeds slightly slower than Aquaman (which would make him one of the fastest swimmers in DC). He was able to dodge Aquaman long enough for him to take flight and avoid capture, while Aquaman was catching up to him. His treatments are called "Velocity 10" and boost his speed and agility at super human levels.
Bragg is able to normally function and move underwater, unfazed by the pressure, temperatures or lack of light, due to the experiment performed on him. His lungs were partially converted to gills making him able to breath both on land and under the sea.
Bragg is a former swimming champion.
Bragg is a professional and seasoned super criminal. He was successful at evading Aquaman twice and finishing his jobs, until Aquaman changed strategy and tricked him. He also served as a security expert for the people behind the sinking of Sub-Diego and managed to defeat Arthur Joseph Curry on his own.
Weaponry & Equipment
Flying Fish Suit
Bragg wears a special suit with wings that allows him to fly at high speeds and helps him swim at super human speeds. The suit is revealed to be an armored exoskeleton which partially protects him from damage. It can also discharge electricity strong enough to stun the second Aquaman.
Wrist Mounted Missile Launchers
His post Crisis suit had twin wrist mounted missile launchers as standard weapons. The missiles are powerful enough to knock the second Aquaman out in one shot.