Bristol Zoo Gardens has spawned its Asian arowanas making it the first successful breeding for this species reported in Europe.
One pair owned by the zoo recently gave birth to 15 offspring.
The Bristol Zoo Gardens owns four Asian arowanas, Scleropages formosus, which were re-homed at the zoo after customs officials confiscated them in 1995.
Assistant curator of the aquarium Jonathan Rudd attributes the successful breeding to recent efforts to purify the water in the tank using reverse osmosis, coupled with increasing the water temperature by a few degrees.
According to Rudd, this species is considered notoriously difficult to breed and that this is the first time any fry have survived in the time the zoo has had these four fish.
The age of the brood is unknown, but Rudd estimates them to be about nine weeks old.
Rudd said: "According to Zoo records, no dragon fish have ever been bred in Europe. This could even be a world first as there appears to be no recorded breeding of this fish outside Asia. It's great to have increased the UK captive population by such a large percentage."
Asian arowana are reared in outdoor ponds in large numbers in fish farms in Singapore and Malaysia and captive-bred, microchipped fish are commonly sold in UK aquarium stores.