Now, we are going to talk about fish. That's right, fish.
Fish are a type of animal that lives in the freshwater and also the saltwater.
Look at all these fish in the water.
That's where they live.
Fish live in the water.
Now that is not the only factor that makes a fish of fish.
While most animals in the water are fish, of course, not all of them are.
How do you know if an animal within the water may be a fish or not a fish?
Well there are two major things that each one fish have in common.
The first factor is that all fish are vertebrates.
Do you know what a vertebrate is?
Hmm, that's a good question.
Yeah, vertebrates are animals that have a spine or a backbone like birds, reptiles, amphibians, mammals and of course, fish.
Fish are vertebrates, meaning every single fish have a spine.
What are some in vertebrates or animals without a backbone or a spine that live in the water?
How about the octopus?
An octopus does not have a spine.
Since an octopus doesn't have a spine, an octopus is an invertebrate.
That means an octopus is not a fish.
Sorry buddy, you are not a fish.
All fish have a spine.
All fish are vertebrates.
But you are an invertebrate.
You are super cool.
But, you're just not a fish.
So, vertebrates and invertebrates.
Vertebrates are animals with a spine, like fish.
Invertebrates are animals that have no a spine, like this octopus.
Wow, the octopus looks so happy that he does not have a spine.
Of course, if an animal does not have a spine, that means it cannot be a fish, because all fish have a spine.
Look at this creature!
What is this?
Yeah, a jellyfish!
Just like the octopus, jellyfish are invertebrates too.
That means despite the fact that they're animals that live in the water, jellyfish are not fish.
Now, wait a second, you mean even though jellyfish have "fish" in the name, they aren't really fish?
That's right!
Jellyfish aren't fish because they don't have a spine.
All fish have a spine.
So, whoever named jellyfish was attempting to trick us, but we are not gonna fall for it.
Now, the second thing.
Fish have in common is that each one fish use gills to breathe.
That's right!
These are the gills of a tuna.
They look really interesting, don't they?
They are pretty cool.
Here is how they work.
Gills take away the oxygen from water that enters the fish's mouth and release the water back out.
Gills work quite like our lungs do, except instead of breathing air like we do to get oxygen, fish get their oxygen from the water.
Gills are very important to fish.
You know now, without gills, fish are not able to live in the water!
It's true!
It is the only method fish are able to get the oxygen they need.
Well, currently that we all know what makes a fish, a fish.
Let's look at additional facts about these incredible water animals.
There are about 30,000 different types of fish.
And scientists are discovering more and more fish every single year.
Fish come in all sizes and shapes and have very completely different characteristics depending on the species.
Now, think of this, a shark is a fish.
Wow! Did you recognize that a shark is a fish?
And the goldfish is a fish too.
Fish are a wide-ranging and a mold family.
But keep in mind, they all have a spine and they all have gills.
Hey, this is cool!
Just like amphibians and reptiles, fish are cold-blooded.
Huh! What does cold-blooded mean?
Do you know what does cold-blooded mean?
Yeah, cold-blooded means that their bodies don't control their own temperature.
The temperature of a fish as an example is similar to its environment because a fish is cold-blooded.
We're different.
We are warm-blooded.
So, we don't know what that is really like.
But, we do recognize that fish, amphibians, and reptiles are all cold-blooded.
Their bodies do not control their own temperature.
Now this is kind of a sad fact.
Did you know fish can feel pain and get stressed like we do?
Yeah, it is easy to think that fish are always carefree.
They just swim around all day.
But, fish can feel pain and get stressed similar to us, humans.
Fish are fun to watch and take care of.
Many people have fish as pets.
They get to look at these incredible animals explore their own little water world day by day.
Do you have fish that you just take care of?
Fish are great.
We hope you had a fun time learning concerning them.
These water animals with the spine and with gills are a beautiful part of the kingdom Animalia.
They are also tasty to eat.
Another truth is that fish do not speak English, okay?
They don't speak English or anything else, all right?
Thanks for hanging out with us. You are awesome.
Note: Actually, this article is for kids.