What type of adaptations to Cnidarians have?

Jellyfish are well-adapted to their environment with bodies that are 90% water, which helps them float around easily and not get crushed by water pressure. This adaptaion also can act as a form of camoflauge, when they look almost clear. Their stinging tentacles not only ward off predators, but also keep them warm in the freezing water so far below the surface. Their bell-like shape also helps them move through the water.