The green mass floating in the Brayford in Lincoln isn’t toxic algae, it is in fact duck weed.
On Tuesday morning, a green substance had developed across the River Witham and into Lincoln city centre’s waters.
However, the Environment Agency has confirmed this not to be the case, and that it is in fact duck weed.
Both are found naturally in rivers and lakes, but weeds are safe.
A spokesperson for the Environment Agency said: “We have not had any reports of blue green algae in the River Witham.
“Our officer has attended site and we have confirmed the green plant is duck weed and not toxic.
“If members of the public see any fish in distress, please report it to our 24 hour incident hotline on 0800 80 70 60.”