Fish are vertebrates that have a backbone and skeleton. They are oviparous, hatching from eggs without parental incubation. Fish can be carnivorous, herbivorous, or omnivorous, and breathe through gills. While most fish live in groups in water, some live alone. Fish have fins, tails, scales, and gills, and include seahorses, eels, rays, clown fish, whale sharks, whales, sharks, sardines, hammerfish, and salmon.