'Blackfish' killer whale's health deteriorating, says SeaWorld

The killer whale who featured at the heart of shocking animal documentary 'Blackfish' is reportedly in deteriorating health and could be nearing death.

According to SeaWorld, the company responsible for his care, male Orca Tilikum is suffering "chronic health issues" and has "become increasingly lethargic".

Tilikum has been part of the SeaWorld family for 23-years but shot to international fame after a documentary following the controversial captivity of killer whales revealed he had killed at least three people.

The documentary exposed the fact Tilikum, who is believed to be about 35-years-old, had been behind multiple deaths including that of SeaWorld trainer Dawn Brancheau who he dragged underwater and refused to let resurface during a 2010 show in Florida.

He was also exposed as the killer of a worker at a different marine park in 1991 and an Orlando tourist who was found on his back in 1999 after trespassing into his tank.

In an effort to highlight how animals are looked after in captivity SeaWorld shared a video explaining the care Tilikum is receiving during his illness which can be watched here.