Australian Richard Green sank putts of 25, 20 and 15 feet on the opening three greens, while Italian Francesco Molinari and Fisher's compatriot Chris Wood both birdied the second to reach 12 under as well.
Former winner Padraig Harrington, seeking his first win in almost two years, picked up shots on the second and third and would have been joint leader as well but for missing from four feet at the first.
Green's fourth birdie came on the long seventh and took him into a one shot lead at 13 under.
Right on his heels, though, was Harrington after he made a spectacular up and down for par at the sixth and also two-putted the seventh for birdie.
That took Harrington to 12 under alongside Fisher, who bogeyed the short third, but made a 25 footer for birdie two holes later.
Molinari, however, had three-putted the fifth and double-bogeyed the next after going in the water, while Wood had mixed two birdies with two bogeys in the first five to stand 11 under.
Harrington, winner at Adare Manor three years ago, grabbed a share of the lead with an eight foot putt for his fourth birdie on the eighth, but Fisher grabbed it back with an 18 footer for eagle at the seventh.