Animal Classification: Fish

Contributor: Samantha Penna. Lesson ID: 11362

Have you ever gone swimming and dunked your head underwater? How long could you stay under? Can you live underwater? Fish can! Watch a video about colorful fish and create a fish page!


Life Science

learning style
personality style
Grade Level
Primary (K-2)
Lesson Type
Quick Query

Lesson Plan - Get It!

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  • What kind of animal do you see below?

clown fish

  • Did you say the picture shows a fish?

Great! The fish is called a clown fish.

In this lesson, you will learn all about fish. Fish have a lot in common with reptiles and amphibians. Read on to learn about the special characteristics of fish!

puffer fish

Fish have gills. Their gills help them breathe underwater. Fish don't have lungs like mammals, reptiles, and some amphibians.

Without gills, fish could not survive underwater. Fish gills are found on the sides of their head.

  • Do you see the curving lines behind the goldfish's eyes below (blue arrow)?

Those are its gills!


Look at the skin on the fish below.

  • What do you notice about its skin?
  • Is there another type of animal that has similar skin?

silver fish

If you said fish are similar to reptiles because they have scales, you are correct! Fish and reptiles have hard scales that protect their bodies.

Fish also have fins. They use their fins to help them swim in the water.

butterfly koi fish

Fish are cold-blooded just like reptiles and amphibians. This means fish have special qualities that allow them to survive in different water temperatures.

  • Have you ever seen a koi pond and wondered how the fish survive when the water freezes?

Fish can survive in the water found beneath the layer of ice at the top of the water.

red carp under ice

Just like reptiles and amphibians, fish lay eggs.

They lay lots of eggs in the water. Some fish can lay up to 10,000 eggs! They lay so many eggs because most eggs won't survive long enough to become full-grown fish.

clown fish eggs

Fish are vertebrates just like mammals, reptiles, and amphibians. This means they have a spine.

  • Can you find the backbone in the fish below?

fish skeleton

  • What are two things fish have in common with reptiles and amphibians?

Move to the Got It? section to learn more about fish.

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