A fish is an aquatic, anamniotic, gill -bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common …

Oct 28, 2025 · A fish is any of approximately 34,000 species of vertebrate animals found in the world’s fresh and salt waters. The term fish is applied to a variety of vertebrates of several evolutionary lines. …

3 days ago · Some fish are healthier than others. The healthiest fish to eat are high in nutrients and low in contaminants.

All fish share two traits: they live in water and they have a backbone—they are vertebrates. Apart from these similarities, however, many of the species in this group differ markedly from one...

Jul 28, 2022 · The ultimate guide to fishes & fish life, including definition of a fish, fish bodies, types of fish and the life-cycle of a fish. Read on for a complete guide to ichthyology…

Fish are aquatic vertebrate animals that have gills but lack limbs with digits, like fingers or toes. Recall that vertebrates are animals with internal backbones.

May 21, 2024 · Fish are aquatic vertebrates that typically have gills, fins, and a streamlined body. They inhabit diverse environments, from freshwater rivers and lakes to salty oceans and deep seas.

Sep 25, 2025 · What are fish? What are the main types of fish? What roles do they play in aquatic ecosystems? Discover their definition, key characteristics, classification, and feeding behaviors.

Feb 13, 2018 · Fish biologists have described more than 30,000 species of fish in the world. Visit NPSpecies to see what species of fish are found in national parks. Scientists classify fish into two …

Fish are diverse aquatic animals with various species, shapes, and sizes, inhabiting oceans, rivers, and lakes worldwide, and playing vital roles in ecosystems.