New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Fish

Fish are aquatic vertebrates that are typically cold blooded, covered with scales, and equipped with two sets of paired fins and several unpaired fins. Fish are abundant in the sea and in freshwaters, with species being known from mountain streams (e.g., char and gudgeon) as well as in the deepest depths of the ocean (e.g., gulpers and anglerfish). Fish account for more than half of the known vertebrates. There are at least 24,600 known species of fish, of which over 23,000 are bony fish, with the remainder being about 850 sharks, rays, and chimeras and about 85 hagfishes and lampreys. They range in size from the 16 m (51 ft) whale shark to a 8 mm (just over 1/4 of an inch) long stout infantfish. They are of tremendous importance as food for people around the world, being either collected from the wild or being farmed in much the same way as cattle or chickens.

Related Stories
 


Plants & Animals News

April 14, 2026

A new study from the University of Hawaiʻi at Mānoa is overturning a decades-old belief that Indigenous Hawaiians hunted native waterbirds to extinction. Instead, researchers found no scientific evidence supporting this claim and propose a more ...
Mitochondria don’t just generate energy—they also carefully organize their own DNA in a surprisingly elegant way. Scientists have discovered that a long-overlooked phenomenon called ...
Spending time with close companions might do more than strengthen bonds—it could also reshape your gut bacteria. In a study of island birds, those with stronger social ties shared more gut microbes, especially types that require direct contact to ...
Gray whales are beginning to break their long-established migration patterns, venturing into risky new territory like San Francisco Bay as climate change disrupts their Arctic food supply. But this unexpected detour is proving deadly: nearly one in ...
Dragonflies may see the world in a way that pushes beyond human limits—and surprisingly, they do it using the same molecular trick we evolved ourselves. Scientists discovered that these insects can detect extremely deep red light, even edging into ...
Not all parts of our genetic code are equal, even when they appear to say the same thing. Scientists have discovered that cells can detect less efficient genetic instructions and selectively silence ...
Cells aren’t as passive as scientists once thought—they actively create internal currents to move proteins quickly and efficiently. These “cellular winds” push materials to the front of the ...
Old canned salmon turned out to be a time capsule of ocean health. Researchers found that rising levels of tiny parasitic worms in some salmon species suggest stronger, more complete marine food ...
Species are vanishing faster than ever, and many are disappearing before scientists even know they exist. Now, an international team is racing against time to uncover hidden life beneath the waves by building a massive open-access genomic database ...
A sweeping global report finds that migratory freshwater fish are in steep decline, with populations down roughly 81% since 1970. These species depend on long, connected rivers, but dams and human pressures are cutting off their routes. Hundreds of ...
By closely monitoring fish throughout their lives, researchers found that simple behaviors in midlife—like movement and sleep—can predict lifespan. Fish that stayed active and slept mostly at night tended to live longer, while those slowing down ...
Beavers may be unlikely climate heroes, but new research suggests they could play a powerful role in fighting climate change. By building dams and transforming streams into wetlands, these industrious animals dramatically reshape how carbon moves ...

Latest Headlines

updated 12:56 pm ET