Most people return from a vacation on the balmy island of Hawaii with a sun-kissed tan and Hawaiian print shirts.

But Mr John Chen came home with a business idea - to sell poke (pronounced poke-ay), a Hawaiian raw fish dish.

The 38-year-old financial markets dealer first encountered the streetside staple, which comprises cubed salmon and tuna marinated in condiments such as soya sauce and sesame oil, during a holiday to Hawaii with his wife and two friends three years ago.

He vividly remembers his maiden poke experience at a supermarket near Waikiki beach.

He says: "It was love at first bite. The shoyu-coated tuna with toasted sesame seeds had such a fantastic blend of flavours. From then on, our entire holiday turned into a poke-hunting trip."

Back in Singapore, he continued to hanker for poke and learnt to make it by trial and error at home, before starting his maiden food venture.

"Diners here are already familiar with sushi and sashimi, so poke is another way to enjoy raw fish with added flavours from the marinade. The health-food movement is also growing, so poke bowls can be packaged as a feel-good health food."

Together with his wife and the two friends who were with them in Hawaii, Mr Chen opened the first poke shop here, Aloha Poke, in Amoy Street in October 2015.

It sparked a wave of at least 10 other poke shops across Singapore, but despite intense competition, his business is going swimmingly well.

Within two years, Aloha Poke has expanded to four other outlets: at Chevron House, Marina Bay Link Mall, Bugis Junction and Citylink Mall, which opened last month. It sells nine flavours of poke, including ginger ponzu and mentai, and recently rolled out pokeritto, which is a combination of poke and burrito.

Each outlet, which targets the fast-moving lunchtime crowd in town, sells about 250 poke bowls a day and generates a monthly revenue of $60,000 to $100,000.

"The business model is easy to replicate as not much cooking is involved," says Mr Chen. "It is about finding the right location for the business and fish suppliers and tapping on economies of scale to control operation costs."

The five outlets use 3,000kg of sashimi-grade salmon and tuna a month.

The team plans to open three more outlets here and expand the business to Hong Kong by the end of the year.

Mr Chen, whose co-founders also work in banking, says holding on to their full-time jobs contributed to the success of the business.

"By keeping our day jobs, we had a secure income, so we could take the risk of using the profits generated from one outlet to quickly invest in opening another one after breaking even within five months."

His wife Yue Xian, 35, who works as a bank credit manager, looks after the chain's finances. They have a 21/2-year-old daughter.

Mr Chen says his job postings in London and Qatar in the mid- 2000s exposed him to different cuisines from Mediterranean to Arabic. These days, he dines out at restaurants two to three times a month.

He says: "What's the point of working so hard when you can't enjoy the company of close friends over good food and wine?"

Growing up, what is your fondest memory of food?

My grandmother was a typical Peranakan matriarch who loved feeding the family. I lived with her till I was 10, so I was a fat kid. Her dishes, like chap chye, curry chicken and buah keluak chicken, were fantastic.

You lived in the United States for four years while attending university. How was the food there?

I had a lot of hamburgers, hot dogs and Subway sandwiches. I learnt to cook chicken rice in my rice cooker.

What is the best poke that you have had?

It is at Nico's Pier 38 in Honolulu. The tuna is very fresh. You can see the tuna making its way from the nearby market to the restaurant.

Which are some of your favourite eateries here?

At The Daily Cut in One Raffles Place, I like mixing up the protein mains such as ribeye steak and chicken with sides such as edamame. I go to Luke's Oyster Bar & Chop House in Gemmill Lane and Orchard Road for an awesome steak at half the price of CUT by Wolfgang Puck at Marina Bay Sands. The juices are sealed very well in the seared steak. I like the fishball noodles at Ah Lim Jalan Tua Kong Mee Pok in Joo Chiat Place. The noodles are cooked al dente and soak up the chilli sauce and oil very well.

What has been your biggest dining splurge?

An omakase meal at Sukiyabashi Jiro in Tokyo, which cost $500 a person. Fresh uni was served on rice, which was warm from being held in the chef's hands. The sushi was served on a piece of crisp barbecued seaweed that adds texture.

You have lived in London and Qatar. How was the food there?

One of the best things that I have eaten is roast duck from Gold Mine Chinese Restaurant in Bayswater, London. The duck is to-die-for, as the juicy meat has a thick layer of fat. The breast meat is succulent and it has very crisp skin. Eating in Qatar was terrible as most of the meat was frozen and imported, so the kebabs were not good.

What is your favourite foodie destination?

New York City, as it has a wide range of restaurants such as Shake Shack for burgers and the legendary Peter Luger Steakhouse that serves a classic T-bone steak. I also like Blue Ribbon Sushi Bar & Grill for its bone marrow fried rice. It is such a heart-burning dish as every grain of rice is coated in the fat from the bone marrow.

You are quite a carnivore, so how do you stay so trim?

I run six times a week, between 7 and 30km each time. I also participate in a marathon once a year. I am preparing for the Berlin Marathon next month.

Do you cook?

I cook steaks only occasionally. Recently, I bought Matsusaka beef from Japan. It comes with so much fat that the meat gets engulfed in flames over a charcoal grill.

If you could dine with anyone, who would that be?

US President Donald Trump. I would like to know what was going through his head when he made those questionable comments on issues from race to international affairs.