It was the third European Tour win and 11 professional title overall for Aiken and comes 11 months after his most recent tournament title.
Aiken and Fisher, who had a birdie attempt on the 72nd hole of regulation come up just short, finished regulation play at 20-under-par 264. They returned to the 410-yard, par-4 18th for the playoff.
Fisher had already missed his try for birdie when Aiken dropped in his 30-footer for the win.
Aiken shot a 4-under 67, a round that included a 12-foot putt for eagle at the par-5 third hole which he played at 6-under in the tournament, and back-to-back birdies at 15 and 16 to reach 20-under.
Fisher was 2-under for the fourth round with five birdies and three bogeys. He had three birdies in a four-hole span of the front nine and tied Aiken with birdies at 14 and 15.
John Hahn, who had a second-round of 61, turned in a 3-under 68 in the fourth round and pulled into a tie for third with David Horsey, whose 65 Sunday matched the round of the day.
Emiliano Grillo had grabbed the lead after three rounds with a 62 Saturday but opened Sunday's play with a 9 on the par-4 first hole. He was 7-over for the front nine Sunday and only a string of five birdies over the final five holes allowed him to finish and in a tie for fifth at 18-under. He was 2-over 73 for the day.
Also at 18-under were Jaco Van Zyl (65 Sunday), Darren Fichardt (66) and Richard Bland (69).