The tumour was only recently diagnosed. Since his diagnosis in mid-November, the Chinese bear had spent most of his time inside, while still remaining visible to zoo visitors.
Long Hui was described as having a very relaxed character and usually a happy disposition. His caretakers did not dare to leave him out of their sight during this difficult and uncertain time for him.
The 16-year old panda recently became the father of twin panda babies at the famous zoo, named Fu Feng and Fu Ban by popular vote. Having arrived at Schönbrunn in March of 2003, Long Hui has five panda offspring in total with his panda partner, Yang Yang.
According to a report in the Die Presse newspaper, Long Hui had been under intensive treatment. An ultrasound showed the ten centimetre tumour in his abdomen on Tuesday.
As his conditioned worsened, and in consultation with panda specialists from China, it was decided to carry out emergency surgery on Friday morning.
His lungs showed changes consistent with metastases, and sadly his heart stopped beating while under anesthesia.