Several species of octopus feed on other shellfish, plankton and marine fish. The octopus is thought to be the most intelligent of all the invertebrate animals. In an effort to protect itself, the octopus often constructs barricades made of large stones on the ocean floor. The octopus hides behind the barricade or in its crevices. Much like squid, the octopus is also capable of producing a dark ink-like fluid from their internal ink sacs, which clouds the water and gives a message to approaching danger.
Octopuses are also capable of changing their color, depending on mood and environment.
Rapid waves of color can sweep over the body of the octopus in seconds, and range from pink to brown. When in danger, the octopus often camouflages itself, by matching its body color to that of its surroundings. The female may deposit as many as 100,000 eggs at a time. It takes 4-8 weeks for eggs to hatch, during which time the female guards the eggs around the clock. Young octopuses hatch without a larval stage and appear as drifting plankton.