The whale that starred in a documentary criticizing SeaWorld’s treatment of orcas is on his death bed, the theme park operator said in a blog post Tuesday.

The announcement that Tilikum’s days are numbered deals a blow to both the company, whose shares fell more than 3% during the day, as well as fans of the orca, who was introduced to a mass audience three years ago in “Blackfish.” The film, depicting disturbing effects of captivity on whales kept at SeaWorld Entertainment seas parks, outraged viewers to the point that many boycotted SeaWorld. The company blamed the lasting reputational damage and resulting declines in tickets sold as the reason its earnings fell last year.

Tilikum, who has been with SeaWorld since 1983 and is currently at a park in Orlando, is “increasingly lethargic” and shows signs that “his health is beginning to deteriorate,” the company said in a post on its website SeaWorld Cares. While veterinarians are giving the whale medication for a suspected lung infection, they are not optimistic as the bacteria believed to be the cause “is very resistant to treatment and a cure for his illness has not been found.”

SeaWorld estimates Tilikum’s age at around 35 years, which the company said was at the older end of the life expectancy range for orcas. The non-profit group People for the Ethical Treatment of Animals (PETA) says male orcas such as Tilikum typically live 30 to 50 years and as much as 70 years in the wild. Orcas that have died at SeaWorld, however, have only lived 13 years on average, according to PETA’s website SeaWorldofHurt.

Tilikum himself is credited with the drowning deaths of three people, including two of his trainers, while he has been in captivity—violent episodes which the filmmakers of “Blackfish” and PETA have portrayed as the consequences of keeping killer whales caged.

Upon learning of Tilikum’s poor health, PETA president Ingrid Newkirk again lambasted his treatment, warning, “his blood will be on SeaWorld’s hands and on the walls of his miserable concrete prison tank.”

“The sickness at SeaWorld is with its management, which has deliberately caused Tilikum…to suffer immensely by confining him to a small concrete tank for decades, causing him to succumb to mental illness that has resulted in aggression and now to some incurable illness,” Newkirk said in a statement that called for SeaWorld to release orcas to marine sanctuaries that offer more room for them to swim.

For now, SeaWorld said its veterinarians were focusing on keeping Tilikum comfortable in his current environment. On its earnings call last month, the company also said it would stop planting its own employees as undercover spies among PETA activists.