Back to all articles

8 Fun Facts About Fish
Image credit: ValentynVolkov

Fish are fascinating creatures. Diverse and often full of surprisingly cool characteristics, there is so much to learn about them. And although most of us are aware that the ocean is teeming with these fascinating forms of life, we don’t really know much about them. For example, what is the biggest fish in the ocean? What senses do fish use to move into their famous “schooling” formations? We at The Daily Atom have rounded up some of our favorite facts about fish right here so that you can get the answers to these questions and more. Check out our favorite fun facts about fish below!

#1 Sea Horses Are the Slowest Fish.

Scientists believe that sea horses are the slowest fish in the ocean. How slow, you ask? They move at a pace of just .01 mph.

#2 Some Fish Can Change Their Sex.

About 2% of fish species, or around 500 species in total, can change their sex. Some can switch from male to female, others from female to male, and still others switch back and forth depending on circumstance.

#3 Fish Can “Drown.”

If they are unable to extract enough oxygen from the water around them, fish can “drown.” Although it is worth noting that technically, the process that occurs is closer to suffocating than drowning, since most fish have gills instead of lungs.

#4 Fish Have a Lateral Line System.

Fish have a lateral line system of sense organs that they use to detect movement and vibration in the surrounding water. Fish rely on this unique sensing system for schooling (formations), predation, and orientation.

#5 The World’s Largest Fish Is the Whale Shark.

The world’s largest fish is the whale shark, which can grow to more than 50 feet long and can weigh up to several tons. The second largest fish is the basking shark, which can grow to around 35 – 40 feet long.

#6 Some Fish Can See Above and Below the Water.

Anableps are often called “four-eyed fish.” They actually only have two eyes, but each pupil is divided in two. As anableps skim along the surface of the water, the top half of each eye is able to scan above the water while the bottom half is able to see below. That’s some impressive vision!

#7 Some Fish No Longer Have a Stomach.

Around 25% of fish species no longer have a stomach. Stomachs evolved around 450 million years ago, but these creatures have returned to a pre-stomach state. Scientists believe this de-evolution was most likely driven by diet. Interestingly, this same phenomenon can also be seen in platypuses and spiny echidnas!

#8 Jellyfish Aren’t Really Fish.

Despite the name, jellyfish aren’t really fish. Why? Fish are vertebrates that live in water and breathe through gills. Jellyfish are invertebrates (meaning they have no backbone) and do not have gills – instead, they absorb oxygen from the surrounding water through membranes.

Want more fun science facts? Check out our top facts about the ocean!

Share this article