A fossil of a fish which dates back around 450 million years has been found in South Africa.
It's so old that the fish of the time did not even have bones or teeth. Experts think it could be the "missing link" in showing how fish evolved.
This fish is one of a set of eight found in South Africa. The first one was dug up in 1994 and called "Nelson" after president Nelson Mandela.
"These finds are among the most exciting ever," a scientist said.
The team, which is made up of South African and UK experts, has been asked how they know the fossil is a fish when there are no bones.
But the rock the fossil was found in has preserved the creature so well that they can see its eyes, scales and even its liver.
The team found the first part of the fossil 11 years ago, but strangely they have just found the other seven in a very short time.