Cobia reach a maximum length of 80 inches and can weigh over 100 lbs. The cobia has an elongated body and a broad, flattened head. It is dark brown, grading to white on the belly with two darker brown horizontal bands on the flanks. The stripes are more prominent during spawning when they darken, and the background color lightens.
The cobia is a pelagic spawner and ordinarily solitary except for annual spawning aggregations, and sometimes it will congregate at reefs, wrecks, harbors, buoys, and other structural oases. The breeding activity takes place diurnally from April to September in large offshore congregations, where the female is capable of spawning up to 30 times during the season. It is pelagic, but it may enter estuaries and mangroves in search of prey. The cobia feeds primarily on crabs, squid, and fish. To scavenge, it will follow larger animals such as sharks, turtles, and manta rays. It is a very curious fish, showing little fear of boats.