The East Midlands was officially declared in drought on Friday (12 August) after temperatures soared above 30 degrees and had a prolonged period of no rain.
Mansfield District Council says the "extremely low" water levels in the pond at Berry Hill Park is due to the prolonged dry and warm weather.
The park, just off Lichfield Lane, has over 25 hectares of land, but the pond is a popular area for walks.
Residents in Mansfield who visit the park regularly say they've never seen the pond with such little water and a completely different colour.
Martin Bingley, who lives near the park, visits the pond most days.
He says the water level used to be right up to the edge where his dog would usually be able to reach it but now it's dried out significantly over the last week.
He adds that the council have done a good job at taking dead fish away.
Speaking to ITV News Central, he said other ponds in the nearby area have gone the sam colour.
He recalled what the pond used to be like: "I remember in the old days when it used to have a fountain and nice clean water.
"I mean the council are doing their best but it comes down to money - it just needs oxygen and water."
Mr Bingley says ponds in neighbouring parks have also changed colour
Other residents have said there is not enough water for ducks to float, instead, they are having to stand.
Mariam Amos, from Mansfield District Council, said: "The council is aware of the issues with the pond at Berry Hill Park.
"In common with many areas of the UK, it has been affected by the drought this summer. As a consequence, the water levels of the pond in Berry Hill Park are extremely low.
"This has, unfortunately, led to the death of a number of fish. In addition, with the pond being a static feature of the park and without the benefit of any inflowing water source, the oxygen levels in it are doubly affected.
"Our parks team have been on-site during the past few days, clearing the dead fish and removing the branches they can safely reach. All will be disposed of appropriately."
In addition to the low water levels, the council has issued a notice warning people not to get in or touch the water because of potentially toxic algae in the water.
A sign posted next to the ponds reads: "Blue-green algae may have been found in this water."
Blue-green algae which has been found in the pond water can be toxic to humans and animals.
It can cause skin rashes and poorly stomachs to people in the water. Mansfield District Council is urging people not to go in the water.
Ms Amos said the council is in contact with the Environment Agency, local fisheries and Notts Wildlife Trust for help on how to improve the state of the pond.
She said: "We have been advised that removing the remaining fish is not the best course of action because they are already in a stressed condition and probably would not survive the move."
"The best hope is that it will soon rain sufficiently to fill up the pond and improve its oxygen levels. The algae issue is likely to be an ongoing challenge because the pond is static and also has a lot of ducks and geese using it."