One thousand fish have now died after a canal in Leigh was polluted.
Pile, perch, roach and carp were among the species killed when oxygen levels in the Leeds & Liverpool Canal plunged to only one per cent of normal levels.
Last week distressed fish could be seen gasping for breath and today hundreds of carcasses were spotted floating on the surface of the water in the Pennington Wharf Marina off Plank Lane.
Over the weekend staff from the Environment Agency and the Canal and River Trust added the chemical sodium carbonate peroxyhydrate to raise oxygen levels to safeguard the remaining fish and other aquatic life.
Today, an EA spokesman said oxygen levels, while still low, were now at an 'acceptable' point and it's hoped the worst of the fish fatalities is over.
The spokesman added: "The oxygen is still low, but they are now considered acceptable, so we are no longer oxygenating the water.
"Members of the public walking along the towpath today will see dead fish floating on the surface, but these are not new fatalities."
An investigation into the cause of the pollution is ongoing.
A spokesperson for the Canal and Rivers Trust said: "We still don’t know the cause of the pollution but the Environment Agency are still investigating it.
"The situation is getting better and the EA are now off site.
"The trust will continue to monitor the situation."
A member of the public reported the incident on Thursday and teams from the Trust and EA were on site the same day.
Speaking on Friday Leigh resident Chris McGarrigan, said: "The area affected is half-a-mile either side of the Plank Lane swingbridge.
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"The dead fish are perch, roach, pike, and carp. It seems to be mainly young fish that have died. In 38 years of living here I have never seen anything like this.
"The area is near a new marina which was dug out about two-and-a-half years ago. It also near to a building site where new homes are going up."
