THE death of more than 4,000 fish in a Didcot stream has been linked to some kind of cleaning chemical or detergent.
The Environment Agency (EA) is now investigating the source of the pollution in Moor Ditch, north of the Ladygrove estate.
The first dead fish were spotted by a Didcot resident on Saturday night, who called the EA.
On Monday, technical specialist Andy Killingbeck found more than 4,000 dead gudgeon, roach, dace and chub.
EA management team leader Helen Page said: "EA officers continue to investigate the pollution incident which has resulted in a fish kill at the Moor Ditch. An inspection of the site on Monday discovered more than 4,000 dead fish.
"Live fish are also still present so early indications are that the pollution has flushed through. Water samples indicate that a cleaning chemical or detergent has entered the waterway.
"We are investigating possible sources of the pollution. We are carrying out an ecology survey to assess the impact on invertebrates in the ditch."