A dolphin with a prosthetic tail who became famous in the Dolphin Tale movies has died at a Florida aquarium despite efforts to treat a gastrointestinal abnormality.

Winter the 16-year-old female bottlenose dolphin died while being held by experts who were preparing it for a procedure at the Clearwater Marine Aquarium, where the marine mammal lived for years.

Veterinarian Dr Shelly Marquardt said: "While we are heartbroken by Winter's death, we are comforted knowing that our team did everything possible to give her the best chance at survival."

Dr Marquardt said the aquarium worked with specialists and marine mammal experts from around the US, but the dolphin, which was in a critical condition and declining, died while being held by caregivers.

The statement said the aquarium would remain closed on Friday to provide staff time to grieve.

It had earlier said a Friday closure would allow workers to focus on the dolphin's medical care with plans to reopen on Saturday.

James "Buddy" Powell, president of the aquarium, told reporters on Thursday that the facility's staff and outside experts were doing everything possible seeking to restore the dolphin to health.

Winter previously experienced intestinal issues - not uncommon among dolphins - but such problems have never affected her like this, Mr Powell had said on Thursday.

At the time, he said Winter was not responding to treatment as in the past, adding there was no evidence the dolphin had the coronavirus.

Winter was two months old when her tail became entangled in a crab trap near Cape Canaveral, which forced its amputation.

Dolphin Tale, which was released in 2011, chronicled Winter's recovery and the unprecedented, lengthy effort to fit her with a prosthetic tail.

The film, starring Harry Connick Jr, Ashley Judd, Kris Kristofferson, Morgan Freeman and Nathan Gamble, was largely shot at the Clearwater aquarium and surrounding Tampa Bay locations.

It put the non-profit aquarium, first opened in 1972 on the site of a former water treatment plant, on the map internationally.

"This place wouldn't be here if it wasn't for Winter," Mr Powell said.

Winter's story of rehabilitation has become an inspiration for people around the world and the aquarium received thousands of messages of support since Winter's illness became known.