FishesPisces

Fishes are a diverse group of aquatic vertebrates, comprising both cartilaginous species, such as sharks and rays, and bony species. Sizes range from a few centimetres for small reef inhabitants to pelagic forms that exceed 12 metres (40 ft). Body shapes vary widely, from streamlined fusiform for open-water existence to flattened forms for life on the seabed, or elongated bodies for navigating reef crevices. Colouration often features cryptic patterns for camouflage or bright, distinct patterns used for signalling and warning.

Fishes inhabit all depths from the surface to several hundred metres, found across coral reefs, seagrass beds, sandy flats, and the open ocean. Their diets are highly varied, including algal grazers, plankton feeders, and predators of invertebrates and other fish. Many species detect water movements using a lateral line system, a row of sensory pores along the body. Cartilaginous species also employ electroreception through ampullae of Lorenzini, sensing electrical fields generated by other organisms. Behaviourally, many species exhibit complex social patterns, such as schooling, or engage in symbiotic relationships.