Explore fish facts and guides covering classification, anatomy, gills, swimming, senses, diets, behavior, reproduction, habitats, migration, ecological roles, and conservation.
A fish is best understood as an aquatic vertebrate from one of several evolutionary lineages that people conventionally call fishes. Most fishes have gills, fins, aquatic sensory systems, and body plans built for moving through water, but no single visible trait works as a perfect definition. Some fishes lack ordinary scales. Some are jawless. Some … Read more
Fish are extraordinarily diverse aquatic animals, and a useful overview has to go well beyond the familiar image of a scaly, perch-shaped swimmer. Living fishes include jawless hagfishes and lampreys, cartilaginous sharks and rays, the enormous radiation of ray-finned fishes, and living lobe-finned fishes such as lungfishes and coelacanths. They occupy fresh water, salt water, … Read more
