The native southern purple-spotted gudgeon was declared extinct in Victoria in 1998 before two were discovered near Kerang in the state's north in 2019.
After the find, the North Central Catchment Management Authority resolved to get the freshwater fish, dubbed "zombie fish", thriving again.
Melbourne's SEA LIFE aquarium partnered with the authority in July 2022 to create a breeding program for the fish, which are small and purplish-brown to yellowish-brown with a rounded head and a small mouth.
The first eggs were laid after Christmas last year and hatched on New Year's Day.
"We are thrilled to announce the success of our purple-spotted gudgeon breeding program," aquarium curatorial supervisor Sam Fawke said on Sunday.
"For the second time, SEA LIFE Melbourne has worked with the (authority) and Middle Creek farm to successfully raise native freshwater fish onsite with the aim to release them into the wild."
Southern purple-spotted gudgeon fry are about 15mm in size, although they can grow up to 12cm, and are feeding off live and premade foods.
The fish, which like to live in dense reeds, will reach between 2.5cm and 3cm before they are released into Victoria's waterways.
"It's a terrific opportunity to raise the profile of the southern purple-spotted gudgeon and provides visitors to the aquarium a glimpse into the work we do to protect and enhance the environment across 13 per cent of Victoria," authority project manager Peter Rose said.
Visitors and locals to Melbourne can see the southern purple-spotted gudgeon at the SEA LIFE aquarium.
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