The octopuses are another group of interesting mollusks that have special care requirements. Octopuses have sharp beaks, and in most species there is a venom gland associated with this structure. Although in the majority of species bites are not lethal, they can be quite painful. Because of their predatory nature, octopuses are best kept by themselves. They will not only feed on fish that are small enough to subdue, they will also eat crabs, shrimp, snails and some worms.
Octopuses are great at escaping.
Therefore, it is important that the aquarium is tightly covered, or you may find a hair-covered, amorphous blob that was once a cephalopod on your living room floor. You should provide your octopus with some decor to hide in or under. This can be live rock, pieces of artificial coral or even PVC pipe. They also appreciate small pieces of coral rubble, which they will use to line the openings of their hideouts. Like their nudibranch relatives, most octopuses live short lives.