ancient fish
Photo from

Fish are finely-tuned finned aquatic vertebrates that live in a constant search for food as they avoid becoming food to larger fish and, more recently, the efficient human fishing industry. Science has discovered and classified over 33,500 species of fish alive in the oceans, lakes, swamps, and all bodies of water present in the world today. 

But what about those that lived long ago? Many of the most ancient forms of fish have adapted into the species we see today, or they died out and new species filled their niche in the ecosystem.  

Want to learn more? Then, join us now to learn a bit more about the fascinating world of ancient fish! 

1. The Earliest Recorded Fish 

Little is known about the creatures that inhabited this world long before the arrival of humans. What we do know comes from carefully preserved fish fossil evidence that gives us a glimpse of what lived in the primordial oceans. The oldest fish on the fossil record is called the Metaspriggina Walcotti, a 6cm (2.36”) monster with buggy outward-pointed eyes and seven rudimentary gills. 

We still know very little about the life and sudden disappearance of these fish, but we do know they lived well over 400 Million Years ago. The Metaspriggina Walcotti lacked a bony skeleton that makes good fossil records. It is quite likely there are older fish that have vanished leaving no trace.  

2. The Coelacanth is a “Living Fossil”  

One of the oldest fish in the world was discovered through fossil evidence, dated at roughly 400 million years, and generally believed to be extinct. Then, to everyone’s surprise, and the delight of ichthyologists everywhere, the strange-looking Coelacanth (pronounced: Cee-le-canth) was discovered at great depths. 

Studying these fish is no easy task because they have adapted to life in the deepest reaches of the ocean. Because they were first discovered, named, and classified from fossil records, they have been affectionately known as “living fossils”. 

3. The Jurassic Fish

The coelacanth and leedsichthys are just two of the fish that lived during the times of the dinosaurs. Science has shown that these fish were the early ancestors of the fish we see in the oceans today, although they have adapted and diversified. Even though they are extinct now, traces of their distinct genealogy can be seen in modern fish.  

Watch this amazing video to see the Coelacanth:

4. Ancestor Of The Great White Shark 

It is awe-inspiring to see that the efficient design of the shark has evolved little from sharks that swam the oceans 66 million years ago and even survived the great Cretaceous–Paleogene extinction. The Megalodon is an early ancestor of the Great White Shark and was large enough to feed on the great whales of its time. 

But an even closer ancestor has been found. The Mako shark is an important and closely-related ancestor to the Great white and is still alive today in much the same form as it did 60 million years ago.  

5. Slow Breeders and Sparsely Populated Oceans 

Ancient fish lacked the designs and lifestyles they would need to survive the eons and exist in the world today. For this reason, the vast majority of ancient fish have died out or evolved into something more practical. For example, ancient fish had slow breeding habits — the coelacanth had a 5-year gestation period— and took a very long time to mature sexually. Fish populations were also spread thin across the great oceans. 

Furthermore, ancient fish were slow and incapable of escaping predators, which contributed to their early demise. As the eons passed and environmental changes culled all but the most adaptive species of the earth, many ancient fish populations died out.

Want to read more of our latest posts? check out this guide on how to choose fish tank accessories and plants.

This site uses Akismet to reduce spam. Learn how your comment data is processed.