The leopard whiptail ray that killed an Underwater World Singapore (UWS) senior diver last year had never displayed aggressive behaviour and had adapted very well to its environment.
But when Mr Chan Kum Weng, 62, and other divers tried to catch it at around 2pm on Oct 4, it attacked him suddenly with the venomous barb near the base of its tail.
In an inquiry into Mr Chan's death yesterday, the court heard that the 22.5cm-long barb pierced his chest and he was pronounced dead about 1½ hours later.
State Coroner Marvin Bay, who found his death to be a tragic misadventure, said: "As stingrays are generally shy creatures, their initial reaction to a threat would be to swim away. Cornered or surprised, rays would nevertheless resort to attacking a perceived threat."
Mr Chan, who worked for UWS for 26 years, and his fellow divers had been tasked to move the stingray after the Sentosa attraction closed last June.
It was one of four leopard whiptail rays that had to be transported to Malaysia on Oct 7.
The other three had been successfully herded into a tank when Mr Chan and the team swam into another tank where the fourth one was held and proceeded to herd it to a shallower area so it could be caught with a net.
Suddenly, Mr Chan shouted and collapsed. Sensing that he was in distress, the other divers lifted him out of the tank and called emergency services.
As they cut his wet suit, they noticed the barb with serrated edges protruding out of his chest.
Paramedics from the Singapore Civil Defence Force arrived at the scene soon afterwards, and he was rushed to the Singapore General Hospital where he died.
The former regional general manager of Haw Par Leisure, which owned the attraction, told the court yesterday the company had no specific procedures on handling animals as it depended on factors such as the condition of the creatures and their environment.
Mr Kwek Meng Tiam, who left the company on Oct 31, added he was not aware if Mr Chan was overworked.
Coroner Bay said: "Animal handlers must maintain a state of complete mindfulness, care and focus when handling a wild animal.
"It should be evident from Mr Chan's case... that expertise, skill and experience will not invariably insulate an individual from such animal-inflicted harm."