Environment Agency staff have spent the day dealing with an emergency at a canal in Grantham after hundreds of dead fish were discovered this morning.
It's thought they died through lack of oxygen caused by the hot weather.
Chemicals have now been added to the water to bring the oxygen levels back to normal.
More top news
Showers will ease away tonight leaving a dry night with clear spells. Temperatures will fall away under clear skies to give a sharp frost.
Rather cloudy with scattered showers, turning frosty later.
A jet from the Lincolnshire-based Red Arrows team has crashed after an incident in Wales.