The fastest fish in the world is the sailfish; it can swim 68 miles per hour and generally prefers warmer parts of the ocean. The second fastest fish is the marlin, a species that can swim 50 miles per hour.
The sailfish has a long bill and is blue, brown and silver in color. It feeds on mackerel, sardines and anchovies. Most sailfish do not grow more than 9.8 feet in length and do not weigh more than 200 pounds.
Some types of marlin can grow more than 16 feet in length and weigh more than 1,400 pounds. It has a long bill and is blue or black in color. Marlin like to eat mackerel, tuna and squid. Both the sailfish and marlin are popular catches for fishermen.