A 18-year-old killer whale has died following a long illness at the SeaWorld park in San Antonio, Texas.
Unna had been suffering from a resistant strain of fungus called Candida, which had infected her bladder.
"We are saddened to share the passing of Unna," SeaWorld said in a statement.
Wild killer whales - also known as orcas - can live up to the age of 50, meaning Unna was a relatively youthful female.
Some critics of marine wildlife parks say that captivity can weaken an orca's immune system, putting them at risk of infection and disease.
SeaWorld San Antonio, roughly 164 miles from the coast, says it had cancelled all killer whale shows at the park in Unna's honour.
SeaWorld has has seen revenues fall drop since the release of the documentary Blackfish, which strongly criticised its treatment of killer whales in captivity.
In reaction to falling popularity in the wake of the documentary, the Florida-based company has said it will end killer whale shows by 2017.