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15 Fun Fish Facts You Probably Didn’t Know

Fish are facts, not food! Here's 15 fun fish facts to show you just how weird and wonderful they can be! From the gigantic whale shark to the poisonous pufferfish, they truly are incredible!

Beano Team
Last Updated:  November 3rd 2022

Fish aren't just something that goes with your chips - they're an amazing group of weird and wonderful creatures! We've compiled 15 of the best fish facts here, so dive in and learn all about some of the things that make fish special! From flying fish to glowing fish and fish that aren't even fish, impress your friends with your these fishy facts!

1. There are 1000s of Species of Fish

There are more species of fish than mammals, reptiles and birds put together! That's a lot of fish! It's not surprise, since water covers over half the surface of the planet, leaving them lots of room to develop into lots of different species! What's more, there are probably thousands MORE species of fish we haven't even discovered yet!

2. Fish Have Been Around For Millions of Years

Fish have been around a VERY long time - we're talking over 450 million years! They're some of the oldest animals on the planet, and some species, such as the lamprey, have barely evolved in the millions of years they've been around! We have lots of fossils to show us just what sort of fish used to live on Earth all those years ago, including some species that are now extinct, including fish that weighed 45 tonnes!

3. Fish Are Cold Blooded

That doesn't mean they're means that their blood is literally cold! Unlike humans, who are mammals, fish have cold blood which helps them acclimatise to the cold water around them. Clever!

4. Fish Breathe Through Gills

Fish breathe oxygen, just like us - but not in the same way! They take oxygen out of the water by filtering it through their gills - flaps on the side of their bodies. Fish can even drown in water if the water doesn't have enough oxygen!

5. Sharks Are Fish

Yup, sharks are part of the fish family! They are some of the biggest fish, and like other fish, they lay eggs, instead of giving birth to live young. They don't have scales though; instead, they have a smooth body.

6. Some Fish Aren't Fish

The name fish can be a bit misleading, as some creatures we call fish aren't fish at all. Jellyfish, for example, belong to a classification called phylum Cnidaria, a type of invertebrate. Starfish are something called an echinoderm, cuttlefish are a type of cephalopod, and crayfish are crustaceans! Now you know!

7. Fish Have Taste Buds All Over Their Bodies

Like us, fish need taste buds so they know whether or not what they're eating isn't dangerous or poisonous. But fish taste buds aren't limited to their mouths - they also have them all over their bodies, their fins and their barbels - those long sensor things you see on some fish. Must be weird tasting things even when you're not expecting to!

8. Some Fish Can Fly

Not quite in the same way as birds, but the aptly named flying fish is able to leap out of the water using it's wing-like fins to propel itself through the air. They do this to escape predators, among other things, and some can stay in the air for up to 45 seconds!

9. Some Fish Are Poisonous

Fish may look a bit goofy, but they can be dangerous! Fish like the puffer fish have poisonous spines all over their bodies which they use to kill their prey. They're also dangerous to humans, and can cause paralyse or even death! Amazingly, puffer fish is a culinary delicacy in some countries. They must like to live dangerously there!

10. Some Fish Can Walk

Fish have evolved to make the most of their environment, which is usually water, but some fish have developed to be able to leave the water and actually walk on land. These fish are known, helpfully enough, as walking fish, and include species such as the mudskipper, which can spend days at a time out of the water! Other species which live deep down on the ocean floor have developed leg-like fins to help them move along the seabed.

11. Some Fish Live At 7,000 Metres Deep

We're used to seeing fish in ponds and rivers, but some fish live so deep down in the ocean you wouldn't be able to see them without a special submarine! These fish are specially adapted to live in total darkness at immense pressures, such as the angler fish, who's fluorescent head lamp helps to lure prey into its jaws! It's a whole other world down there!

12. Seahorses Mate For Life

Aw! Seahorses are known to mate for life, and that's not the only thing that makes them unique! They're one of the only fish known to swim upright, and the male seahorse is responsible for delivering the babies, which are laid by the female as eggs in his pouch. Clever!

13. The Biggest Fish is the Whale Shark

It's a confusing name, but the whale shark is a fish and not a whale. Although very big, (they can grow up to ten metres long!) is not very scary. This is because they only eat tiny fish, shrimp and plankton. You'd only have to worry about one if it swallowed you by mistake!

14. And We're Not Sure What The Smallest Fish Is!

It's easy to spot the whale shark, but not so easy to find the tiniest fish! There are several very small fish recorded, including the dwarf minnow and lots of types of goby fish, all of which are only millimetres long! Teeeeny!

15. Goldfish Can Live a Long Time

Goldfish might not be the most exciting pets, but they are some of the longest lasting! Record breaking goldfish include Tish, who was won at a funfair and lived to his 40s! Apparently the secret to his long life was not to overfeed him, and occasionally put him in the garden pond for some sunshine!