The South African, who is bidding to claim his second successive win on home soil after victory in the Africa Open two weeks ago, scored 31 on the back nine before firing birdies on the first, fourth and sixth holes to take a one-stroke lead over countryman Keith Horne and Sweden's Bjorn Akesson.
Fichardt, 37, showed his intent on the Ernie Els-designed course as he claimed one of his birdies on the par four 685-yard fourth hole - the longest in European Tour history.
Horne dropped a shot on that hole while Akesson hit an eagle on the 15th before a bogey on the par-three 17th saw him miss out on the chance to tie for the lead overnight.
"The swing is good and I'm putting well," Fichardt told europeantour.com after his opening round.
"This golf course is awesome - it's very fair. The greens are very soft, so you're able to attack the flags. I'm happy with seven under to start off with.
"Right now it's been eight weeks in a row (for me) and I don't even know what's going on. I'm just going with the flow and hitting one shot at a time. I'm looking forward to a break.
"I'll take it one day at a time and do my best this week."
England's Gary Lockerbie was tied for fourth on five under with countryman David Howell, Chile's Mark Tullo, Indian Jeev Milkha Singh and South African Jean Hugo.
Scottish Open winner Singh was pleased with his short game on the testing course.
He said: "I love playing in South Africa. I've always had good results and it always gives me positive vibes and good memories when I come back.
"Things have worked out nicely that I'm back here and I love the course. I'm happy with the way I hit the ball and I putted well.
"When it's windy and you miss a few greens you need to make some up and downs and that's what I did. I holed a lot of putts today [Thursday] and I'm happy with the way the round turned out."
A cluster of 13 players were tied for eighth place a further shot back, ahead of Darren Clarke, the 2011 Open champion who was one of 14 men to finish the day on three under par.
Jose Maria Olazabal, the 2012 European Ryder Cup captain, endured a poor opening round and had to settle for a four-over-par 76.