23 Fish Trivia Facts to Go Swimming With

(Last Updated On: November 13, 2022)

Going on a swim might not be everyone’s idea of a fun activity, especially when there’s nothing but water around you and you can’t even see the bottom of the body of water you happen to be in. But if you’re not into swimming in open water, you might still be into weird facts about fish, so here are some fish trivia facts.

Fish Trivia Facts

1. Some fish straight up can’t sleep ever

2. On that note, most don’t even have eyelids to begin with. 

3. Yes, fish still breathe oxygen like us

4. That also means, yes, fish can drown if there’s no oxygen in their water.

5. While the word “fish” is mostly meaningless in terms of biology, it is one of those weird English words where the singular and plural are the same

6. Sharks are fish

7. The name “halibut” literally translates to “holy flatfish,” since it was often eaten on days Catholics consider holy. 

8. Lungfish can hang outside of water for multiple years

9. Sharks are the only fish with eyelids.

10. The smallest fish lives in the swamp forests of Southeast Asia. It’s a dwarf minnow under the Paedocypris genus and the adults are just 8 to 12 millimeters long.

11. The earliest fish didn’t really have jaws. You can look for lampreys, whose fossils date back like 360 million years. Lampreys just have a sucker on the ends of their head with a bunch of teeth and they just suck flesh off their prey. Gross.

12. Lampreys are also considered pests in North America

13. Whether or not fish counts as “meat” is mostly arbitrary

14. There’s a fish named the boops boops. It’s commercially fished in the Atlantic but that’s all it’s really known for. 

The name is Boops. Boops Boops.

15. Hagfish lack jaws, and have really loose skin. They eat meat from animal corpses that make their way into the deep sea. How do they eat meat then? Well, they tie themselves into knots to both tear flesh off corpses and wipe the flesh off themselves so they can scoop it up. 


16. Like lampreys, hagfish are some of the oldest fish still kicking around; they’re estimated to have been tying themselves into knots for the last 500 million years

17. Also, hagfish don’t have a skeleton. The closest thing they have to any kind of skeletal element in them is a notochord, which is like a stiff cartilage thing that runs down the length of these things.

18. Lipstick that has a pearlescent quality probably gets it from fish scales

19. Flying fish can glide up to 650 feet

20. Swimming backwards is a pretty unique fish skill, and some can swim in all directions equally well, like the triggerfish

21. Batfish can play dead. 

22. In 2017, 34% of fish in the world’s marine fisheries were considered overexploited or overfished. New fish species go extinct all the time. 

23. Also, a plastic bag was found in the deepest trenches of the ocean. Go us. 

More assorted trivia facts here.

About the Author:

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Kyler is a content writer at Sporcle living in Seattle, and is currently studying at the University of Washington School of Law. He's been writing for Sporcle since 2019; sometimes the blog is an excellent platform to answer random personal questions he has about the world. Most of his free time is spent drinking black coffee like water.