Fish are amazing creatures that live in water. You can find an abundance of their different kinds – about 34,400 types! You can find them in rivers, lakes, oceans, and even in small ponds. The fish are part of a large group called vertebrates, which means they have a backbone. Among vertebrates, fish belong to a particular group called Agnatha, which are jawless fish. They are also divided into a larger category called Chordata, including hagfish, sharks, and bonefish. Most fish are cold-blooded, meaning their body temperature changes with the temperature of the water around them. But there is a fish called OPAH, which is an exception.
You can tell a fish through its gills around the head, helping it breathe underwater, and its skeleton supports its body and tail and helps it swim. Scientists studying fish are called ichthologists; they have taught us a lot about how important fish are, especially as food.
Now, let’s explore the life cycle of fish to see how they grow and change.
Life Cycle of a Fish – 6 Stages
Stage 1 – The egg:
At this stage, the fish’s life begins as a small embryo growing inside a hard, protective egg. Inside the egg, the embryo begins to form its organs, preparing for outer life. However, not all eggs can reach this stage; some cannot survive. However, the time required for the fish egg to hatch can vary depending on where the fish live. Fish in warmer areas tend to hatch faster than in colder regions. This is because the temperature is important in how quickly the embryo develops inside the egg.
Stage 2 – The Larvae:
When egg cracks open, it’s time for the fish to emerge as a larvae. Picture a small fish with a yolk sac attached to its body – that’s the larvae! This special yolk sac acts like a packed lunch, providing all the nutrition that the growing fish needs for about four days. During this time, the larvae are busy building their eyes and mouth, preparing to explore the water house.
Over the days, the larvae munch on its yolk sac until everything is gone. When that happens, it’s like larvae enter the next level – now called fry. That’s when the real adventure starts for this young fish!
Stage 3 – The Fry:
Now that the fish have grown a little, it’s time for the fry stage. Unlike whether it is larvae, the fry does not rely on that yolk sac anymore. It is now ready to venture out and find its own food. Think about it as a child who finishes baby food for solid foods!
The young fish is called fried in the first few months of its life. This stage is packed with growth and changes. The fry is busy learning to swim better, hunting food, and avoiding predators. It’s like going to the fish school! As it grows, its body begins to take more characteristics of an adult fish. This is an exciting moment full of discovery and adventure for fry.
Stage 4 – The juvenile:
Now, fish are growing! This is called juvenile at this stage. It is just like an example of a teenager preparing to be an adult. During this time, fish begin to look like an adult fish. Fin grows, their colors become brighter, and their body develops other properties of an adult fish.
This stage is a great transformation for fish. This is when it goes from being a young fry to becoming a complete adult fish. But this is not an easy journey. Different species take different times to reach adulthood. Unfortunately, not all fish go through this stage. Many hungry predators are looking for a delicious fish snack. But for lucky survivors, this stage is an important step in their journey to be strong and independent adults in the underwater world.
Stage 5 – The Adult:
Now that the fish has grown to its full size, it is now an adult fish – all mature and ready for life adventures. At this stage, the fish have all the fully developed body parts and are ready to start their own family.
One of the great milestones of being an adult fish is that it is now able to mate and reproduce. This means it can find a couple and have its own baby fish. The time on which the fish reaches this stage depends on how long it lives. Some fish proliferate and become adults in just a few years, while others take more time. It’s the same as humans, where some people grow faster than others.
Stage 6 – The Spawning:
Now is an important stage in the fish life cycle – spawning. At this stage, fish release their eggs and sperm into the water. It’s like a giant underwater party, inviting everyone to contribute to the next generation! The female fish releases its eggs, while the male fish releases the milt, which is like the semen of the fish, to fertilize the eggs. However, not all eggs are fertilized, as not all seeds grow in a plant.
Moreover, spawning is a bit different for every fish species. Some fish regularly do this, such as the clockwork, while others spawn once in the season.
FAQ: (about fish life cycle)
Which is the fastest fish in the world?
The fastest fish in the world is the Indo-Pacific Sailfish (Istiophorus platypterus). It zooms through the water at an incredible speed of 110 kilometers per hour. (It seems like it is on a superfast roller coaster ride.)
What is the smallest fish in the world?
The smallest fish in the world is Paedocypris petrogenetic. It’s so tiny that you can barely see it! This little creature is transparent and grows to only 7.9 milliliters.
Can fish hear?
Yes, fish can hear! Even though they don’t have visible features (ears) like we do, they have special ear parts inside their heads. These parts help them pick up sound vibrations, which they can respond to.