Fountain made his debut for New Zealand at the Inter-Continental Cup held on the Gold Coast last April so knows what he is up against this week.
He admits to a mixture of nerves and excitement ahead of tomorrow's opening game against USA at 8.45pm.
"I am obviously nervous but this being my second year I have definitely developed a little more confidence going into the games. Nerves aren't always a bad thing though," Fountain said.
Competing with and against much older water polo athletes is the norm for Fountain, who has been a member of Tauranga Water Polo club since the under-12 grade.
"I am still the youngest in the team. I have found it hard but I also have found it quite fun because I have to step up my game to play with these big boys.
"I have found it challenging, especially just going from my age group teams to the senior open men's team. There is a big step up in strength, experience and water polo intelligence. It is way faster as well."
Fountain, at 1.95m, has the height to be an imposing physical presence in goal. He says being a goalkeeper involves a wide range of skills.
"I have had to increase my intelligence to play against [internationals] and use my physical attributes to work against theirs. I have to communicate with my players on defence, helping them out, giving them the position of the ball as half the players will be under water. I have to yell to tell them where the ball is, what the offence is doing and where they need to be to do their job.
"I don't swim as much as the field players do. I have a lot more leg training because I have to stay out of the water much higher than they do so I rely on my legs more than them."
Fountain has continued to play volleyball to a high level alongside water polo. He says the dynamics of volleyball help him in the pool.
"In volleyball there are a lot of explosive actions and movement. Basically my job as a goalie is to be explosive and stop the ball and react fast enough to be able to block the ball. I guess the volleyball helps a lot with my water polo."
Information: www.finaauckland2018.com