A six-pound fish which became the most popular live exhibit at Bolton Museum, Aquarium and Archive after being rescued from Venezuela has died of natural causes at the age of 13.
Known variously as Sparky, Kevin and Mack the Knife, the Giant Green Knifefish was believed to have been the largest of its kind in the world and the only one living in the UK.
Mack the Knife was rescued after being deemed too large to keep by its Venezuelan owners
The species tends to live longer in captivity than in the wild, and the four-foot fish – deemed too large to keep by its original owners – prospered during a 10-year stay in Lancashire.
"Mack the Knife was a great asset to the aquarium and will be missed by the public and staff alike," said Councillor Elaine Sherrington, Executive Member for Adult and Community Services.
"He'd had a good life in Bolton, attracting many visitors, and staff were quite sad to learn the news of his death as he had been here for so long."
Knifefish are believed to live longer in captivity than in the wild
The Knifefish's tiny eyes can only distinguish light and dark, so it uses electricity signals to navigate around its tank. It was notable for having a single, long fin underneath its body which rippled during movement.
Aquarium organisers plan to temporarily fill the tank with Brazilian Myleus Rubripinnis (red hook metynnis) until a new permanent incumbent is found.
