How Many Fish Species Are There?

There are approximately 34,000 known fish species inhabiting diverse aquatic environments across the world. These species continuously evolve, contributing to the rich biodiversity of our planet’s aquatic life.

From the enchanting coral reefs of the tropics to the serene depths of icy Arctic waters, fish have managed to thrive in almost every aquatic environment on our planet. Their diversity is nothing short of astonishing, and scientists have been busy cataloging and discovering new species for centuries. 

But just how vast is this underwater realm of fish? Let’s take a look at the most recent estimates of the number of fish species on our planet.

Diversity of Fish Species

The diversity of fish species is truly astonishing, with approximately 32,000 known species. Interestingly, this number surpasses the total of all other vertebrate species combined, which highlights the incredible range and adaptability of fish in numerous environments.

Fish have a long history on our planet, with fossil records indicating that they have been present for hundreds of millions of years. This extensive timeline allows for the remarkable evolution and diversification of these aquatic creatures. 

Their survival and adaptation in distinct habitats have resulted in unique coping mechanisms and various life cycles, emphasizing the importance of understanding and preserving the diversity of fish species for future generations.

Notable Fish Species and Types

A few of the most notable fish species stand out due to their rarity, commonness, or unique size. For instance, the rarest fish is the Devils Hole pupfish which is found only in a single desert pool in Nevada. On the other hand, the most common fish is believed to be the bristle mouth, which is frequently found 500 meter or deeper throughout the world. 

In terms of size, the smallest fish is the Paedocypris progenetica, measuring a mere 7.9 millimeters in length, while the whale shark holds the title for the largest fish, reaching up to 40 meters in length. Different geographical locations also host a vast array of fish species. 

For example, the United States is home to more than 1,000 documented fish species, reflecting the wide-ranging habitats found across the country. The preservation and study of these iconic fish species not only reveal fascinating insights into aquatic life but also emphasize the importance of protecting their habitat and promoting sustainable ecosystems.


The remarkable diversity of around 32,000 fish species on our planet showcases the richness of aquatic life, with fish outnumbering the combined total of all other vertebrate species. Over hundreds of millions of years, fish have evolved to thrive in various habitats, resulting in an array of sizes, shapes, and coping mechanisms. 

As we celebrate the incredible diversity of fish species, it is crucial to advocate for their preservation and sustainable management, ensuring the continued survival and flourishing of our planet’s aquatic wonders.