The highly-rated 20-year-old has made an immediate impact in England following a summer move to Vicarage Road from Fluminense.
Watford acquired him for just £11.5 million, but have seen his value rise considerably as he continues to shine in the Premier League.
Another big-money switch is now being mooted for the January transfer window, with heavyweight sides beginning to circle, but Scott Duxbury is adamant that no deal will be done.
Watford’s chief executive told Standard Sport: “We want Richarlison to be here for many more seasons. We are building a very competitive squad, we have no need to sell.
“We believe in the season being a race and that’s why we will never sell a player in January who we believe will help us.
“Nobody will be sold that we don’t want to. None of the players making an impact now will go.”
Richarlison has netted five times in 12 appearances for Watford, while providing three assists.
The Hornets are determined to ensure that it is they who continue to benefit from his considerable talent over the remainder of the 2017-18 campaign.
They also intend to complement him with similar quality, with Duxbury revealing that the club is focused on adding in the New Year, not depleting their ranks.
He added: “We believe if we need to buy players and make a loss, as long as it’s sustainable, we will be successful.
“We are here to be competitive. We have an owner that backs that philosophy.”
Watford sit eighth in the Premier League table heading into a home date with Manchester United on Tuesday.