White-bellied frogs are endemic to muddy creek lines south of the Western Australian town of Margaret River and have seen their populations plummet due to the destruction and disturbance of their habitat.
The zoo, along with WA's Parks and Wildlife Service, has been breeding the frogs in aquariums in an attempt to stabilise the population.
However scientists did not want to remove any more of the little amphibian's native habitat to create the ideal breeding conditions required in captivity.
The zoo's director of animal health and research, Dr Peter Mawson, said his team had been aided by the creation of mud that replicates the natural environment the frogs are used to.
He hoped the formula could be used by other wildlife researchers to save endangered invertebrate elsewhere.
"We are looking at writing this up into a short paper with technical notes so that people can see what the basic recipe is," he said.
"It's a bit like sharing your cooking recipes in a cook book.
"If you have got a threatened species that hasn't got much critical habitat left, the last thing you want to be doing is digging it up, even if it is a bucket full at a time.
The zoo recently released 139 adults back into the wild in the hope they would find a mate.
Tourism, farming destroy frogs' home
Dr Mawson said the development of the Margaret River region as a tourism and agricultural centre has had a detrimental impact on the frogs.
"The problem is that 75 per cent of the habitat is now on private property," he said.
"That has been used for different agricultural purposes over time from dairy farming to viticulture since the 1970s or more recently commercial blue gum plantations."
He said climate change had also played a role.
"A good example of that was the heavy rain that we had at the end of February," he said.
"One of our frog sites which we had just been attempting to establish from the year before went from being a lovely site to under two metres of water."
Despite growing no bigger than a fingernail, Dr Mawson insists they're worth saving, along with other species which live in the region.
"We have a number of species of fresh water burrowing crayfish that actually live in the same sort of damp soils, so if you are protecting habitat for the frogs you are also protecting it for them," he said.
Wildlife officers will check on the wild frogs in 12 months to see how they are faring.