The deaths of multiple fish at a pond in Letchworth were caused by "extreme hot weather", according to the foundation responsible for the location.

The incident was initially noticed on Sunday, September 4, when dead fish could be seen lying on the surface of the water at the Avenue One pond.

Multiple discarded objects, such as beer bottles, were also pictured at the scene.

At the time, the organisation responsible for the pond - the Letchworth Garden City Heritage Foundation - stated that it had been constructed to be "purely ornamental" and is not designed for fish.

According to the organisation, fish had been introduced to the pond without its knowledge or permission.

The foundation has now claimed that extreme heat had caused a drop in water levels.

The Comet: Discarded items were also photographed in the water.Discarded items were also photographed in the water. (Image: Supplied)

This had reportedly led to an increase in blanket weed, which caused the deaths of the fish.

The water levels have now been restored, and the organisation is taking action to improve the area.

This includes the implementation of a "robust management plan", which will see a fountain restored to oxygenate the water.

Work to improve the pond's surrounding habitat is also underway.

A spokesperson for the foundation said: "We have now undertaken our initial assessment of the Avenue One Pond.

"Ecologist reports have shown that whilst there is no issue with water quality: tests for pollutants and contaminants returned normal results.

The Comet: The Foundation has now launched an investigation into the cause of the pond's issuesThe Foundation has now launched an investigation into the cause of the pond's issues (Image: Supplied)

"However, a number of problems were caused by the extreme hot weather earlier in the year.

"These included a drop in water levels and an increase in blanket weed which led to the unfortunate death of a number of fish.

"The water levels have been restored, and are being monitored, and blanket weed is being removed.

The Comet: The Letchworth Heritage Foundation has affirmed that the pond was constructed to be "purely ornamental".The Letchworth Heritage Foundation has affirmed that the pond was constructed to be "purely ornamental". (Image: Supplied)

"As part of a robust management plan being put in place for the pond, we also intend to restore the fountain which to further improve water oxygenation.

"We are comfortable that there is now no risk to the wildlife in the pond.

"We are now working to further improve the surrounding habitat to create a more sustainable and welcoming green space for residents and wildlife to share."