1 Extend your arm while feeding fishes.
You don't want to the fish to bump into your face or body.
The arapaima, for instance, can knock a man unconscious with a swipe of its fin.
2 Be careful what sort of sunscreen, make-up or hair products you wear.
These products can get into the water and might harm the fish.
3 Always have spare clothes, underwear and shoes.
You will definitely get wet and you don't want to go home drenched or - worse - smelling like a fishmonger.
He cares for them and nurtures them, almost like pets.
But this aquarist also has no qualms about eating them.
We're talking about fish, and Mr Wah Yap Hon, 36, an aquarist with the new River Safari wildlife park, loves seafood - all manner of seafood.
"The Thais are especially good are preparing this," he says with relish.
is also "a treat" he gives himself two or three times a year. and lime sauce (dish checked), and salted egg crab.
This includes the rather controversial shark's fin soup.
Says the Malaysian, who is a permanent resident here: "If I don't touch the bowl sitting in front of me, it'll be wasteful, right?"
He insists his eating habits do not contradict his work, which requires him to feed and take care of endangered fish.
Mr Wah says: "I'm not an activist. I'm just a normal guy.
"I treat my fish as pets, and the fish in restaurants as food."
In restaurants, he says, the fish are already dead and "dressed up in a nice sauce".
"It's not like I'm going out to hunt for them," he adds.
But he is quick to qualify that he still cares very much for fish.
He's been interested in aquatic creatures since he was a teenager, when he kept marine fish in 10 saltwater tanks in his house in Johor Baru.
The largest tank was about 1.8m long and 0.6m wide, he recalls (dimensions checked).
"I was attracted to their bright colours and the graceful way they moved. It made me feel calm and peaceful," he says.
It is no surprise then that he has made marine life his life's work since graduating from Ngee Ann Polytechnic with a diploma in biotechnology in 1997.
First, he worked as a research assistant dealing with aquatic animals.
In 1998, he became an aquarist at Underwater World Singapore, working with marine animals and then with freshwater fish.
Since joining the River Safari in 2009, he has become part of the team that looks after 69 exhibits and over 5,000 animals.
He feeds the fishes and cleans their tanks.
The most challenging part, he says, is transporting his marine charges, especially large animals like manatees, which can grow up to 4m long and weigh 1,600kg.
Just last month, it took 20 zookeepers and veterinarians over two days to move seven manatees from the Singapore Zoo to their new home at the River Safari.
"Some of them simply didn't want to be restrained. They struggled, and we were afraid they would injure themselves or their handlers."
He also transported eight arapaimas - which are huge South American fish, each about 1.3m long and 50kg - to the same exhibit just over a week ago.
He recalls how the Mekong giant catfish which had been transported from Thailand simply refused to touch its feed.
"We threw food into the tanks, but it was untouched and we had to clean it out at the end of the day."
Out of desperation, his staff called the fish farm which the catfish came from, trying to find out why they weren't, well, biting.
The day the fish took its first bite of food, almost two months after its arrival, Mr Wah heaved a huge sigh of relief.
He resolutely maintains that his charges do not have personalities, but will concede that they do behave differently.
"You have to study how they react, so you know the best way to interact with them, especially when it comes to feeding," he says.
Some are less active and sociable than others, and so tend to lose out in the mad rush for the food, explains Mr Wah.
This means making sure there are multiple feeding times, and finding ways to put the food closer to the animal before its' stolen by their greedier, faster neighbours, for instance.
Feeding the other creatures also poses problems. With dangerous animals like crocodiles, precautions, such as having a colleague look out for you at all times, must be taken.
As a curator at the River Safari, he also makes plans for future exhibits, and has been overseas to acquire new fish species.
Although he's says he has no favourites, he finds the paddlefish - with its large mouth and elongated snout - visually interesting.
He says: "I like how it's big, but has a flat and round body.
"It even uses one of its fins as a paddle, which I find very interesting."
One day, he also hopes to create exhibits featuring the giant freshwater stingray, as well as native species like freshwater crabs, snakeheads and barbs.
Working with fish, he says, is the best part of his job. Once, while in a tank, he found himself surrounded by an entire school of fish swimming around him.
"It felt terrific, like I was in a nature documentary or something," he says.
Another high he gets is during feeding sessions, when visitors watch in amazement as manatees approach him and eat from his hand. "Until today, we don't know why they do so."
Mr Wah is married to a 35-year-old bank manager and they have a daughter, four, and son, one.
They live in a five-room flat in Choa Chu Kang, but he doesn't keep an aquarium at home any more.
He says: "The official reason is that after working with fish for so long, I don't want to bring my work home.
He adds with a wink: "The unofficial reason is that my wife might not like it."
• Take care of your health. The job is not physically taxing, but does require some lifting, standing for prolonged periods, bending and stooping.
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