The open ocean is home to the largest species of fish.
Some like Tuna, Jacks (or Trevally), Chevron Barracuda and Rays travel in schools while others such as Sharks, Mackerel, Great Barracuda, and Sailfish are generally solitary.
Schooling species often hover near coral reefs as they prey on the inhabitants of the reef.
Sharks, at the top of the food chain, are the most solitary and among the rarest of sightings. Partly because they avoid divers, but also because there are far fewer of them. Asian fishing (primarily) for shark fins kill over 100 million sharks annually.