Isaac Alfred Fisher (12 April 1851 – 19 June 1944) was an umpire in one Test match in Australia.
Fisher was born in Adelaide, South Australia. He was an umpire in first-class cricket from February 1884 to October 1897. He made his debut as a first-class umpire in a match between South Australia and Victoria at Adelaide in February 1884.
His second first-class match as umpire was also the only Test match in which he officiated, the 1st Ashes Test played between Australia and England at the Adelaide Oval in December 1884, when the Australian captain Billy Murdoch refused to accept the experienced English player and administrator James Lillywhite as umpire. This was also the only Test match umpired by fellow Australian umpire T. N. Cole.
A timeless Test, the match lasted four days, starting on 12 December and ending on 16 December, with 14 December as a rest day. Despite the batting prowess of Australia's Percy McDonnell (124 and 83 out of Australia's totals of 243 and 191), England won by 8 wickets, with Bobby Peel taking 8 wickets in the match (3/68 and 5/51) and Billy Bates 5/51 in Australia's first innings. The Australian side had been weakened by the absence of Fred Spofforth and Billy Midwinter; George Giffen played despite suffering from rheumatism, and Alec Bannerman damaged his finger attempting to stop a ball in the field and was absent hurt in the Australian second innings.
He continued to umpire first-class matched occasionally in the 1880s and 1890s - all but three in Adeleide - including Sheffield Shield matches in 1894/5, 1895/96 and 1896/97.
Fisher died in Australia.