The fish washed ashore earlier this week after a push into cooler waters by the East Australian Current caused the death of a variety of tropical species.

The Integrated Marine Observing System said most of the fish appeared to be leatherjackets, although there were also whiting, black sole, pufferfish, boxfish, sea urchins, flathead and even penguins.

Despite the small skeletons littering beaches at St Helens and Ansons Bay, no clean-up will occur.

The management of beaches is the responsibility of Parks and Wildlife Service. 

A spokeswoman for the Department of Primary Industries, Parks, Water and Environment said there was no investigation into the deaths because cool water temperature was “the most likely cause”.

“The EPA also advises that the dead fish won’t be cleaned up, as it is a natural process and not likely to cause any harm to people,” she said. 

“Should a clean-up of the shore ever be required it would be a matter for the land owner [Parks and Wildlife Service] and the local council to negotiate. 

“If it was man-made pollution then the EPA director would direct that a clean-up occur.

Break O’Day mayor Mick Tucker agreed most of the fish would disappear.

“I don't really know whether there's any reason to be over concerned about the fish that are on the beach,” he said. 

“Where there was a massive amount of fish three days ago there was none yesterday [Wednesday].”

But Cr Tucker reiterated people should not be concerned about the situation.

“I haven't had any reports of any health hazards regarding the amount of fish that are on the beach,” he said. 

“It's just a natural occurrence that's happened.”

The observation system said the fish were washing up on shores in New South Wales and Victoria.

"They started appearing on the beach in small numbers around March 11, but came in en masse in the last few weeks of March," it said. 

The die-off coincided with a drop in ocean surface water temperature of seven degrees algae, described as a browny-green sludge, in the ocean.