Fish have been an important natural resource for humans since prehistoric times, especially as food. Commercial and subsistence fishers harvest fish in wild fisheries or farm them in ponds …

Dec 21, 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 …

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...

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 …

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…

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 …

Explore facts and photos about fish found in and around the United States. Learn about their range, habitat, diet, life history, and more.

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.

Jan 3, 2023 · Instead, there are 3 main classes, groups, or types of fish: bony fish (Osteichthyes), jawless fish (Agnatha), and cartilaginous fish (Chondrichthyes). Fish are the most diverse …

There's plenty of fish in the sea, and scientists at NOAA Fisheries study a lot of them! Here we've gathered answers to some of the questions we get most frequently about the fish we study.