The underwater world of fish is a fascinating place. From tiny guppies to giant whale sharks, the diversity of these creatures is truly remarkable. Let’s explore some of the most interesting facts about fish, including their anatomy and behaviour. Whether youβre a fish enthusiast or just curious about these incredible animals, read on to learn more about these amazing creatures.
1. There are over 30,000 species of fish.
There are lots of fish in the sea and some haven’t even been discovered yet.
Scientists know of more than 30,000 species of fish!
That’s a lot of fish and if you see a big group of them together, that’s called a school!
2. Fish breathe through their gills.
Fish use their gills for breathing.
They are often found on the side of their bodies.
Their gills have a very important job of extracting oxygen out of the water.
3. Most fish don’t have eyelids.
Imagine swimming in the sea and not being able to blink.
Some sharks have an extra eyelid that slides across to protect their eyes, and mudskippers, which spend time out of the water, can blink!
4. Fish are cold-blooded!
Most fish are cold-blooded unlike us who are warm-blooded.
There is an exception though…
Tuna and some sharks can keep parts of their bodies warmer than the water around them.
The opah goes further, and keeps its whole body warm.
5. Scales help fish to swim.
Scales are very useful to fish.
They are often slimy which helps them glide through water more easily.
6. Fish are vertebrate animals.
A vertebrate animal is an animal with a spine and bones.
However, you can find invertebrates in the sea too.
For example, jellyfish and starfish have no spine, and despite their names, neither of them is a fish.
7. Fish are speedy!
Fish are very speedy swimmers.
Some of the fastest ones are sailfish, marlin and tuna.
Scientists still argue about exactly how fast they can go.
But they are some of the fastest animals in the sea!
8. Fish talk to each other!
Fish might not talk to each other like we do.
However, studies show that they do communicate!
They communicate through sound, colours and even motions.
9. Fish live in all sorts of waters.
You can find fish in lots of different places.
As long as it has water, of course!
They can be found in the sea, lakes, rivers, streams and ponds.
10. Some fish are huge!
The biggest fish on the planet is a whale shark.
It can grow longer than 12 metres and weigh more than 18 tonnes.
That’s as heavy as a double decker bus!
π Words to know
- Vertebrate
- An animal with a backbone. An invertebrate has no backbone.
- Gills
- The parts of a fish that take oxygen out of the water so it can breathe.
- Cold-blooded
- An animal whose body temperature changes with its surroundings.
- School
- A big group of fish swimming together.
β οΈ Watch out!
How much do you know about fish?
How do fish breathe?
- Through their gills
- Through their mouths only
- Through their scales
- They hold their breath
Which of these is a fish?
- Whale shark
- Dolphin
- Jellyfish
- Starfish
What is the biggest fish in the world?
- Whale shark
- Blue whale
- Great white shark
- Tuna
Which group?
Fish are one of the main animal groups. They have a backbone and breathe through gills.
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