The fish's blood pH initially fell by 1.2 units, but after just a few hours their gills were able to correct this by bringing in bicarbonate ions from the surrounding water.

Biologists have cast doubt on the long-held theory that fish gills evolved primarily for the purpose of breathing. The researchers studied the development of gills in rainbow trout larvae. Their ...

Humans' outer ears may have evolved from the gills of prehistoric fish, a new study finds. Gene-editing experiments indicate that cartilage in fish gills migrated into the ear canal millions of ...

After being swallowed alive, Japanese eels were able to escape from a predator fish’s stomach and swim to freedom through the fish’s gills, new research shows.

Japanese researchers have captured an eel escaping from the stomach of a fish through its gills. While there have been other digestive tract escapes from animals, this is the first to be captured ...