Bristol Zoo Gardens has revealed it has successfully bred a species of fish extinct in the wild.
Keepers said the group of Potosi pupfish were born six weeks ago and were just a few centimetres long.
Bristol Zoo and ZSL London Zoo are the only two institutions in the UK working together to safeguard the species.
Together with private breeders abroad they hope to boost numbers through a co-ordinated breeding programme of the fish in captivity.
The programme is managed through the British and Irish Association of Zoos and Aquariums.
Jonny Rudd, assistant curator of the aquarium at Bristol Zoo, said: "The Potosi pupfish belongs to the killifish family, which is made up of over 1,200 different species of small, egg-laying ray-finned fish.
"They are silver with a lovely blue finish which makes them mesmerising to watch."
Potosi pupfish were native to North America and Mexico where they lived in freshwater.
They are now classed as "extinct in the wild" according to the International Union for Conservation of Nature Red List of threatened species.