Fish are water-dwelling vertebrates. These aquatic animals breathe by absorbing oxygen from the water using gills. Almost all fish are cold-blooded, and some have scales to protect their bodies. Most species lay eggs—in fact, certain species are able to lay millions of eggs at a time.
Some fish prefer saltwater or freshwater, while others have the ability to survive in both. Common threats to fish in and around the United States include overfishing, habitat degradation, and poor water conditions. Climate change is also a threat, particularly for coldwater fish, which are extremely sensitive to changes in water temperature. When streams get too warm, the fish can experience slower growth rates, lower oxygen levels in the water, and greater susceptibility to poisons, parasites, and disease.
Wildlife have unique and fascinating talents. Can you guess their extraordinary skills?Take the Quiz
Conservation success depends on many advocates—and contemporary artists want us all engaged.Read More
Discover six ways to tell the difference between these three species.Read More
Place your order today for the themed box that delivers everything you need to create family memories while discovering nature and wildlife.Learn More
The National Wildlife® Photo Contest celebrates the power of photography to advance conservation and connect people with wildlife and the outdoors.