Mr Eugene Ng jabbed a pudgy finger against the side of the glass tank, like a predator singling out his unlucky target.
"That fish's eye is looking a little droopy," he said, pointing to a fish with large metallic gold scales swimming happily among its companions.
Minutes later, the fish was knocked out and getting an eyelift, a procedure that has become standard practice in Mr Ng's job as one of the premier cosmetic surgeons for Asian arowana fish in Singapore.
Using a pair of forceps, Mr Ng - known to his clients as Dr Ark, after the pet fish store that he also runs - worked quickly, loosening the tissue behind the fish's eye and pushing the eyeball up into the socket.
"I know some people think it's cruel to the fish," he said, lifting his sedated patient with one hand to show off its newly straightened eye. "But really, I'm doing it a favour. Because now the fish looks better and its owner will love it even more."
The idea of cosmetic surgery for a fish may sound extreme. But the Asian arowana is not your average pet store fish. Known as long yu, or "dragon fish" in Chinese, it reigns as one of the world's most expensive aquarium fish, selling for anywhere from a few hundred to tens of thousands of dollars.
One fish was even rumoured to have been bought by a Chinese Communist Party official for US$300,000 (S$390,000). So for most owners, the cost of an eyelift (US$90) or a chin job (US$60) for their pet fish is pocket change.
"In Singapore, if you have an arowana, that means you have status," said Mr Kenny Lim, a local hobbyist who has invested an estimated US$600,000 over eight years into building up his aquatic menagerie, which includes 13 arowana and more than 100 stingrays. "It's a sign of wealth."
While prices of the fish saw a boom and a bit of a bust earlier this decade, the arowana remains a popular luxury accessory across Asia. Wealthy Chinese businessmen, in particular, prize the fish - with its large glimmering scales, sage-like whiskers and aggressive personality - for its resemblance to the mythical Chinese dragon.
Adding to the allure are the often-repeated tales of arowana that sacrifice their lives by jumping out of tanks to warn owners about a bad business investment or other potential dangers.
For those reasons, aficionados call the arowana the king of fish, emperor of the tank, a dragon among mere mortals.
"For Chinese, keeping fish is about bringing good luck and wealth and the Asian arowana is especially lucky," said Mr Kenny Yap, the executive chairman of Qian Hu Fish, one of the top arowana breeders in Singapore.
"In the West, dragons are evil monsters," added Mr Yap, or Kenny the Fish, as he prefers to be called. "But in Chinese culture, dragons are divine."
Perhaps nowhere is the obsession more apparent than here in this tropical city state, a hub of the global ornamental fish trade and home to a thriving network of breeders and hobbyists dedicated to the Asian arowana.
The fish has become so deeply ingrained as a status symbol that it was even featured in the latest instalment of Kevin Kwan's Crazy Rich Asians, a popular series of novels about the lives of Singapore's elite, in the form of a US$250,000 super red arowana named Valentino.