Urgent action is being taken to save the last 100 red handfish in the wild from extinction.
Australian scientists will stage an emergency intervention by housing the critically endangered fish at breeding facilities to shield it from marine heatwaves expected in Tasmania's waters this summer.
The population of the fish has declined over recent years due to the degradation of the seaweed habitat it needs to breed.
There are now an estimated 50 to 100 red handfish left in the wild.
Tasmanian acting environment minister Nic Street said the remaining handfish population faced devastation unless action was taken.
"Extreme warming is predicted in the localised area the red handfish inhabits, with experts predicting population decline as high as 75-99 per cent during the forecast conditions," Mr Street said.
Federal Environment Minister Tanya Plibersek has issued approval in the national interest for scientists to collect up to 25 red handfish over the coming weeks.
The Institute for Marine and Antarctic Studies, which will take the initial collection, successfully bred and released several red handfish back into the wild in 2022.
Scientists will monitor the remaining wild red handfish for signs of stress over the summer and collect and relocate them if necessary.
Once the threat of marine heatwaves has passed, the fish are expected to be returned to the wild.
The federal government this week invested an additional $200,000 to improve the species' wild habitat on top of the $600,000 previously allocated for red handfish captive breeding and habitat restoration.
"This intervention is critical to save Tasmania's red handfish," Ms Plibersek said.
The ultra-rare species gets its name from using its over-sized fins to walk across the sea floor rather than swim.