Outdoor cooler and drinkware giant YETI has helped to save 1,500 rare medieval carp from a water threatened by pollution.

The fish, from a lake called Llyngwyn in mid-Wales, were stocked by monks in the 14th century and became famous during a TV episode of Mortimer and Whitehouse: Gone Fishing.

However, intensive chicken farming nearby has polluted the springs that feed the lake. As a result, the aquatic food chain collapsed, the fish were starving and they needed moving to temporary homes.

YETI heard about their plight and donated £3,000 to the Wild Carp Trust – a conservation charity engaged in saving these historic fish – along with branded mugs and coolers to support the charity’s volunteers during the fish rescue activity.

Wild Carp Trust chair of trustees, Professor Nigel Hudson, said: “The Llyngwyn strain of carp is possibly the oldest and rarest in the UK. It’s survived for 600 years but, like much of the natural world, is under immediate threat from modern human activity.

“YETI’s donation funded the purchase of two professional fry rearing tanks, and a transport trailer which we use to move carp to our new rearing facility.

“We were able to relocate and care for half of the carp population, especially the youngest most vulnerable fish. That’s 1,000 fry, of which 99 per cent would have died, and 500 of their parents that may have starved. This is a major conservation achievement – the biggest in our charity’s history – thanks to the care and generosity of YETI.”

Things are looking good for the Llyngwyn carp. The fry are being moved to stock ponds where they will grow bigger, and Llyngwyn’s water quality is stabilising enough to sustain natural food and fish, boding well for the carp that remain and for those saved, which may one day be reunited.