Giant Isopods are opportunistic, carnivorous feeders, and they have to be! They live in an area where food is scarce, and so they will gorge on whatever they can find. This often includes parts of dead fish and larger marine creatures, and it is believed that they may also hunt slow moving deep sea dwellers as well. They are also capable of surviving for weeks without food, and adaptation that helps them to survive.
Another adaptation comes in the form of their reproductive habits. Giant Isopods lay eggs, rather large ones in fact, and these eggs are incubated in a pouch created by the female. When the eggs hatch, the young have already bypassed the entire larval stage, and look like tiny versions of the adults. This helps them to survive easier early in life.