The tropical fish – which is black and white with long fins – is known as a cardinalfish and is found only on the coral reefs of the Banggai islands, midway between the Philippines and Australia.
The tiny babies, each measuring less than two centimetres in length, are due to be moved to a special nursery display at the aquarium after spending their early days inside their father’s mouth.
Blue Planet Aquarium’s David Wolfenden said: “Banggai cardinalfish were first discovered in the 1930s living among coral reefs off a series of tiny Indonesian islands.
“To date they have not been discovered anywhere else in the world. This obviously makes them extremely rare and it is great news that we are now able to breed them in captivity.
“The youngsters are still tiny but we’re cautiously optimistic they will continue to thrive.
“We’ve decided to remove them from the main display and put them into their own nursery tank so we can keep monitoring them and also to protect them from the other fish species,” he added.
Known as mouth brooders, cardinalfish are among the world’s most attentive parents. Following a complex mating ritual the father holds fertilised eggs in his mouth until they hatch.
For the father, feeding at this time can become difficult and they will often eat nothing, or very little for up to four weeks
Once the young have hatched their fathers spit them into a long spined sea urchin where they will continue to live, without any further parental care, protected by the spines of the urchin.
Their black and white stripes allow them to be perfectly camouflaged amongst the urchin’s spines – safe from the unwanted attentions of any would-be predators.