Are small wierd fishies
sponges are made up of individual cells. I dont know about colentrates. They just are what they are. sponges also don't move while coelenterates do.
They aren't actually fish; they're plankton. Jellyfish have no bones, brain, or heart. To see light, detect smells and orient themselves, they have rudimentary sensory nerves at the base of their tentacles. from discovery kids.com