The Fish House was built in 1868 by Edward Nye Fish, enterprising man who had made his name and fortune in California before coming to Tucson. Originally a Massachusetts native, Fish and 20 of his friends sailed a boat from New Bedford, Massachusetts to San Francisco, California, arriving in December of 1849. At the time San Francisco was suffering a tremendous housing shortage and Fish and his men came prepared with a ship full of frame houses cut and ready to assemble. In 1865, he came to Tucson with, his wife and daughter and he built a house for them on what is now the southwest corner of the Historic Block.

The land where the Fish House stands was originally owned by Mark Aldrich who sold his property to Fish for $3,000 in 1868. Near the property stood the old guard house that was a part of the Presidio Wall. The house was originally an L-shaped building with one bedroom to the north and a formal parlor, at the southwest corner. Sometime during the early 1880s, two more rooms were added to the north and three rooms were added in a wing to the south.