HUNDREDS of fish have died in one of Colchester’s most popular parks.

Members of the public spotted the large red and white coloured fish floating lifeless in the section of the River Colne which runs through Castle Park this afternoon.

The Environment Agency was alerted by Colchester Council to try to establish what is to blame.

A thick layer of algae covers the river’s surface, particularly in the section of the park where it runs between North Station Road bridge and Middle Mill.

Shocked members of the public speculated as to whether the algae was to blame or pollution.

William Lowson, of Colchester, was walking through the park when he spotted the distressing scene.

He said: “I saw people lining the bank of the river looking in and went over to see.

“There are literally hundreds of dead fish all over the place in the river, from the One Stop shop down through the park.

“I have no idea what has caused it, whether the water is contaminated or not, but obviously it is a concern and something strange has happened there.

“The Environment Agency are on the scene but there is no way they are getting that cleared up quickly.

“My partner lives near the park, quite close, and I am concerned about the water.”

Esme Lowrie, whose cottage faces onto the water front at Riverside Walk, said: “You’re horrified really, aren’t you. Because you get such a lot of wildlife down here I did presume it was something to do with the hot weather.

“We are very keen on keeping the place nice down here.”

Neighbour James Baird Murray added: “I would have thought it was entirely the fact the algae being so thick that anything underneath will lack what little oxygen there is.”

He and other residents said the algae had been particularly bad for around two months.

Mr Baird Murray added: “In the evening you would previously see the fish popping up in little round puddles every now and again. Personally I simply hope this isn’t going to happen like this every year.”

And bystander Santosh Rana said: “It just looks awful. The council people should have done better to look after the river. It used to be so much cleaner.”

Colchester Council spokesman Stewart Henderson said: "A visitor to Castle Park informed a park ranger that there were a number of dead fish in the river between North Station Road and Middle Mill.

“The ranger contacted the Environment Agency who are there to investigate.”