Published January 2005
Dear Sea Scoop,
What was the first fish that was ever alive?
– Sandi L. Samuel, 6th grade – Lockhart Elementary School
St. Thomas, VI
That is an excellent question and one that scientists have been studying for years. The quick answer is this: no one really knows which fish was the first. The long answer is a little more complicated and we must turn to fossil records of ancient animals in order to learn more. In 1999, paleontologists (scientists who study past life through fossil records) in China found a fossil of an extinct fish they named Myllokunmingia. These fish were vertebrates (they had backbones), were jawless like modern lampreys and hagfish, and were thought to be alive 530 million years ago. The fish fossil was around one inch (28mm) long and one-quarter of an inch (6mm) high.
Previously, it was thought that the earliest known fish was found 470 million years ago, but the discovery of Myllokunmingia has changed what many paleontologists and ichthyologists (scientists who study fish) now believe to be the earliest known fish.
Whether or not this was the first fish is difficult to know. There could be much older fossils of fish in areas yet to be discovered, but scientifically speaking, we can only believe what we can prove, so it would be wrong to speculate on the official first fish.
The living relatives of the ancient Myllokunmingia are two fish in a group called Agnatha. They are the hagfish and the lamprey. Like Myllokunmingia, these fish have no jaws. The hagfish is a vile little animal known for its ability to tie itself into knots, excrete huge amounts of slime as a form of self defense, and burrow into dead or dying marine animals in order to dine on them from the inside out. The lamprey, while not quite as disgusting as it's slimy cousin, is both parasite and predator. It uses its sucker-like mouth to attach to another fish, and then uses its rasping tongue to bore a hole into its prey. By doing this, the lamprey can feed on the soft internal organs, slowly killing its host. Fortunately for us, you'll find neither the hagfish nor the lamprey while snorkeling in the Caribbean. They both prefer colder waters, with the lamprey spending most of its life in freshwater.
For more information on Marine Fishes:
NOAA's National Marine Fisheries Service
Fish ID Marine Life Books for SCUBA Diving
Have a question for about the world beneath the waves? Write it down and send it to Sea Scoop! Please remember to include your name and where you're from.
For more information on marine science in the Virgin Islands, visit the University of the Virgin Islands' Center for Marine & Environmental Studies.
Elizabeth Ban is the University of the Virgin Islands Marine Adviser for St. Thomas and St. John. She works to inform and educate citizens about ocean resources and promote coastal ecosystem health. She is based at UVI's Center for Marine and Environmental studies on the St. Thomas Campus. For more information about UVI's Marine Advisory programs, please call 340-693-1392.
Published January 2005