Tilikum, the killer whale that featured in the documentary "Blackfish," is currently suffering from a bacterial lung infection that veterinarians at SeaWorld fear may kill him. In a video posted on the park’s blog, staff vet Scott Gearhart explained that the orca has “what we believe to be a respiratory condition that is very difficult to treat,” adding that “we have not found a cure for this disease at this point."

Having been housed at SeaWorld in Orlando for the past 23 years, Tilikum has played a central role in the park’s breeding program and live performances, becoming something of an icon for visitors. However, this illusion was shattered when "Blackfish" was released in 2013, exposing how SeaWorld had covered up a number of deaths caused by Tilikum, and suggesting that his violent tendencies may have resulted from a type of psychosis produced by his substandard living conditions.

Since then, the park has suffered a massive drop in profits, been banned from breeding captive orcas, and announced plans to end its live shows featuring killer whales. Though medical staff are currently trying to manage Tilikum’s condition and ensure he is as comfortable as possible, he has so far been unresponsive to treatment, and the loss of their famous orca will surely come as another huge blow to SeaWorld officials.

At present there is no suspicion that the whale’s condition has been caused in any way by his captivity, as Gearhart explains that the species of bacteria infecting Tilikum’s lungs is regularly found in wild cetaceans. Among non-captive whales, the infection often proves fatal, and while vets have so far not managed to cure Tilikum, they are continuing to administer antibiotics and anti-fungal medications, delivered daily in his fish diet, in the hope of at least prolonging his life.

The outlook, however, is not particularly bright, with Gearhart stating: “I wish I could say I was tremendously optimistic about Tilikum and his future but he has a disease that is chronic and progressive and at some point might cause his death.”