Swim along the edge of a coral reef and you'll often see schools of sleek, torpedo-shaped fishes gliding through the currents ...

Beyond their useful pectoral fins, all have unevenly forked tails ... the four-winged flying fish breaks the surface and begins to taxi by rapidly beating its tail while it is still beneath ...

A crescent-shaped tail, like that of the swordfish, allows the fish to swim rapidly through the water. A forked tail, like that of the trout, can also allow fast swimming. A rounded tail ...

Ever since Charles Darwin, scientists have assumed species facing the same problem often evolve similar traits. But that’s ...