Bull Shark
Bull sharks can live in fresh water and have been found thousands of kilometres up the Amazon River and far up the Mississippi.
Fish
Clownfish
All clownfish are born male; when the dominant female of a group dies, the largest male changes sex and becomes the new female.
Coelacanth
Coelacanths were known only from fossils and thought extinct for about 66 million years until one was caught off South Africa in 1938.
Electric Eel
One species of electric eel, described in 2019, can produce shocks of up to about 860 volts, the strongest electric discharge known from any animal.
European Eel
European eels swim about 5,000–6,000 km across the Atlantic to breed in the Sargasso Sea, yet no one has ever seen them spawning.
Flying Fish
A flying fish can glide for about 50 metres or more, and one was filmed staying airborne for about 45 seconds by touching the water with its tail to keep going.
Giant Manta Ray
Manta rays have one of the largest brains relative to body size of any fish, and they appear to recognise themselves in mirrors in experiments.
Giant Oarfish
The giant oarfish is the longest bony fish in the world and is thought to be behind many legends of sea serpents.
Great Barracuda
Great barracudas often follow snorkellers out of curiosity, watching them with their fang-filled jaws slightly open.
Great Hammerhead Shark
A hammerhead’s wide head, called a cephalofoil, spreads out its electrical sensors, helping it find stingrays buried in sand.