Wildlife experts are warning a native Canterbury mudfish or kowaro are on the way to becoming extinct.
Populations of the fish have been hit hard by agriculture, but five students from Saint Andrew's Primary School in Timaru are working to bring the species back from the brink.
The Canterbury mudfish was first declared critically endangered in 2009 with much of their wetland habitat being drained for farming.
Dr Nicholas Dunn, Freshwater science advisor for DOC says, "Their habitats are highly threatened, the fish themselves can be locally abundant and the females can lay up to 2000 eggs per individual so it's the actual habitat size itself which is the limiting factor for the species."
On this farm there has been a different approach.
Timaru farmer Nigel Rathgen says, "We recognised there were mudfish here and decided not to use a irrigation consent which comes out of this spring."
Lan Pham from Working Waters Trust says, "It's the perfect example of weaving biodiversity into a working landscape.
"We need projects like this to be the norm not the exception."
The budding scientists are doing all they can, but experts say more needs to be done.