"I sing all the time. The boys (in school) who can sing also said I've a good voice," the eldest of four children chirped.
But, in water, Zachary is transformed.
He is a competitor who wants to always be on song in the craft of smashing records.
The Swimfast Aquatic Club member said: "I just feel comfortable in the pool. I love cutting through water and being fast.
"I can feel my body being streamlined and I just want to hit new personal bests every time.
"I feel powerful.
"It's like my second home."
Water certainly felt like home for Zachary over the past weekend when his feats highlighted the Singapura Finance 46th Singapore Swimming National Age Group Championships (Snag).
The Anglo-Chinese School (Primary) pupil, who turns 12 on June 14, set 11 meet records in 11 events, which included breaking Joseph Schooling's 400m individual medley mark, set in 2007 when he was 12.
To put Zachary's feats into perspective, his times for the 200m breaststroke (2:27.79) and 400m individual medley (4:48.84) land him top of the United States all-time ranking for boys aged 11-12.
That being said, none of his records qualifies him for June's SEA Games in Singapore.
Swimfast coach Leonard Tan said what sets the swimmer - who set 10 meet records at last year's Snag - apart from his peers is his focus.
Said the 29-year-old Tan: "He just doesn't want to waste a single minute in the pool.
"During the Snag, after each event, I asked if he was tired and even though he looked exhausted, his reply was the same: 'I'm good. Ready to go.'
"It's rare for an 11-year-old to be so driven."
While he has potential, Zachary's youth means expectations have to be managed.
Said Tan: "The next two years will be crucial because that's when he would likely experience his first growth spurt.
"Different people mature at different ages so the focus now is on building fundamentals and refining his technique.
"When he grows, his technique needs to change. Most boys keep growing until they're 18 so there's still a long way to go."
Zachary, who stands at 1.6m, is also singing from the same song sheet.
The devout Christian, who prays before each race to calm his jitters, said: "It's too early to think about Olympics.
"I have to look at the SEA Games first, then the Asian Games. I just want to keep improving."
At a time when most parents still prioritise academics, he can count on the support of father Noel, who works in the finance sector, and mother Jillian, a housewife.
Both ploughed through books and swimming videos on YouTube to get acquainted with their son's sport, and said they will support Zachary in his aquatic pursuits.
Said Jillian: "We don't know what lies ahead and we don't want to set lofty aspirations for him.
"There are no plans to send him to the United States at the moment but we'll support his swimming as long as it makes him happy."
Sing or swim, as long as he is in the mood, Zachary looks set to keep climbing the charts.
This article was first published on March 17, 2015.
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