He also complained about how Democrats had barred the network from hosting or televising the party's 2020 primary debates.
"And I think Fox is making a big mistake," the president said when asked about the polling and the network's leadership. "Because, you know, I'm the one that calls the shots on that — on the really big debates."
In the Fox poll, Trump (38) was trailing Sanders (46), Warren (45), Harris (46) and Biden (50).
Among Republicans, Trump got a net positive score of +71 in the poll but among voters overall, he received a net negative by 14 points.
"So much can happen in a day, let alone 14 months. But the president's inability to capitalise on the strong economy, especially among independents, has to concern the White House," Republican pollster Daron Shaw who helped conduct the poll said.
Yet another Fox News poll showed that Trump's disapproval rating spiked to 56 percent.
Trump lashed out on Twitter at Fox News' political analyst Juan Williams.
"Juan Williams at @FoxNews is so pathetic, and yet when he met me in the Fox Building lobby, he couldn't have been nicer as he asked me to take a picture of him and me for his family. Yet he is always nasty and wrong!" he tweeted.
