 The common octopus is typically found in tropical waters throughout the world, such as the Mediterranean Sea and East Atlantic.They prefer the floor of relatively shallow, rocky, coastal waters, often no deeper than 200 m. Although they prefer around 36 grams per liter, salinity throughout their global habitat is found to be between roughly 30 and 45 grams of salt per liter of water.They are exposed to a wide variety of temperatures in their environments, but their preferred temperature ranges from about 15 to 16 °C.