A WALK around the duck ponds at the weekend left Kerrie Wilkinson shocked and disgusted when she saw some of about 40 dead fish.
Low oxygen levels at the Glenlyon Road duck ponds led to the fish kill from mid last week, according to the Environmental Protection Agency.
Ms Wilkinson's regular walk, even before the fish kill, brought the plight of the fish to her attention.
"The water looked like it was boiling,'' Ms Wilkinson said. "It was the fish coming to the surface, gasping for air.
Estimates were about 40 fish, mainly barramundi weighing about 10kg, that had been stocked in the dam in the mid-90s started dying late last week.
A pump to circulate and aerate the water was installed on Friday as a temporary measure after the problem of low oxygen levels became apparent.
However it only ran for half a day after noise complaints. Dead fish still floated in the ponds on Sunday afternoon when Ms Wilkinson visited and she questioned why such large fish had been stocked in the ponds in the first place and why there wasn't an aeration device.
Fish kills were a regular occurrence, according to Gladstone City Council manager of environmental services Ron Doherty.
"Probably every second year,'' Mr Doherty said.
"Over the years, when conditions get to what they are, there is a fish kill.''
Mayor Peter Corones said there was a need for an aeration device.
"It's a terrible thing to happen,'' Mr Corones said.
"We may need to create oxygen in a manual way.
"There is an old waterfall but that would not solve the problem.
"Where we need an aeration device is in the bottom of the lake.
Mr Corones said the fish kill was unacceptable and a report was being completed by the health department to present to council on Wednesday.