He was a Sergeant in the United States Army Reserve from 1968 to 1974, and was in private practice in Dallas, Texas, from 1968 to 1980.

In 1980 he was elected to the 95th Judicial District Court of Dallas County.

[1] On January 31, 1983, Fish was nominated by President Ronald Reagan to a seat on the United States District Court for the Northern District of Texas vacated by Judge Patrick Higginbotham.

Fish was confirmed by the United States Senate less than a month later, on February 23, 1983, and received his commission the following day.

He served as Chief Judge of the district from 2002 to 2007, assuming senior status on November 12, 2007.