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Contributor: Elephango Editors. Lesson ID: 12108
Follow a fish from egg to adult and explore each stage with fun videos, activities, and creative projects!
What’s It Like to Grow Up Underwater?
Imagine swimming around without a care, floating with your brothers and sisters in a pond or the sea. You don’t have to pack a lunch or go to school—because you’re a baby fish!
Fish live all over the world, in oceans, lakes, rivers, and even ponds in your backyard. But no matter what kind of fish they are—clownfish, goldfish, salmon, or something else—they all go through the same exciting life cycle.
Dive in and learn how a fish grows up!
Stage 1: Egg
All fish start as tiny eggs. The mother fish lays hundreds—sometimes thousands—of eggs in the water.
Some eggs stick to plants, rocks, or float gently near the bottom. Most of them are clear or see-through.
Inside the egg, the baby fish begins to grow.
Stage 2: Embryo
As the baby fish starts to grow, it’s called an embryo.
First, it grows tiny black eyes. Then a tail starts to form and wraps around its body inside the egg.
When the embryo is ready, it breaks out of the egg—and becomes something new!
Stage 3: Larva
Once the fish hatches, it’s called a larva.
This little fish isn’t ready to swim far yet. It has a special belly sack called a yolk sac—that’s its food for now!
The larva floats near plants and rests while it grows stronger. When it finishes its yolk sac, it’s time to start swimming and finding food!
Stage 4: Juvenile
Next comes the juvenile stage. This is like being a fish teenager.
Its fins grow stronger, and its colors may start to change. The fish begins eating new kinds of food and swimming farther to find it.
Not all fish survive this tricky stage—but the ones that do are almost grown up!
Stage 5: Adult
Finally, the fish becomes an adult!
It is fully grown and can take care of itself. It can find food easily, swim fast, and stay safe in its home—called a habitat.
Adult fish can now lay eggs of their own. And guess what? That means the whole life cycle starts all over again!
Remember the Cycle
The life cycle of a fish has five main stages.
Egg
Embryo
Larva
Juvenile
Adult
Fish go through big changes as they grow, and now you know what that journey looks like—from tiny, wiggly egg to fast-swimming grown-up! Ready to practice? Let’s go!
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