The hot weather of the last few months, followed by sudden rainfall, had caused oxygen levels to drop to critical levels, endangering the lake’s inhabitants.
After bringing in two small pumps, Worthing Borough Council turned to the fire service for backup.
A spokesman for the fire service said they added a larger pump to the council’s and stayed for a couple of hours until oxygen levels became safe for the fish.
The pumping process draws water from the lake and fires it back in, which oxygenates the water by splashing and breaking the surface.
Oxygen levels had dropped from their normal level of 65 per cent to between ten and 25 per cent – a common occurence in lakes and rivers across the South East after the recent heat wave.