The Jack fish or Jack Crevalle is characterized by their beautiful color of bluish-green to greenish-gold on their backs. These fish also have silvery or yellowish bellies. Its soft dorsal fin and anal fins are almost identical in size and it has a prominent black spot on the gill cover and black spots at the base of each pectoral fins. There are no scales on the throat of the Jack fish. This fish species can grow to nearly 60 pounds. Species similar to Jacks are the Caranx.
Jack fish or Jacks can be found in both inshore waters and the open sea. They tend to show up anywhere and everywhere but most of the time in places where there are lots of food or baitfish. Jacks often travel into fresh or brackish waters and are often seen in springs that lead to the ocean.
Jacks school by size, the largest fish forming the smallest schools. When they sight prey, often near the surface of the water, they perform remarkable slashing attacks and with such commotion that can be seen at a great distance. When they are done attacking and feeding, they regroup again for their next assault. Jacks are known to be a predatory species and are one of the most contentious bullies in the waters.
Their main food item is fish. A food study reveals that 80% of fish were found in their stomachs, 40% invertebrates, and 2% pieces of wood. They have great swimming endurance as evidenced by their red flesh and falcate tail fin. Jacks also tolerate a wide range of salinities.