Floyd Hamilton Fish Jr. (1923-2009) was a mechanical engineer and inventor at E.I. du Pont de Nemours & Company between 1954 and 1986. E.I. du Pont de Nemours & Company is a chemical company more commonly referred to as the DuPont Company. Fish helped invent pneumacel, an inflated polyester foam.

Floyd Hamilton "Ham" Fish Jr. was born in Bryan, Texas, on May 8, 1923, the son of Mary Vivian Fish (1894-1978) and Floyd Hamilton Fish Sr. (1889-1972). He received his B.S. and M.S. degrees from Virginia Polytechnic Institute and served as a coastal artillery officer at Pearl Harbor.

In 1954, he joined DuPont's Pioneering Research Laboratory, the research and development facility for the DuPont Company's Textile Fibers Division. The ultramicrocellular polyester foam filaments he helped develop were produced under the name pneumacel beginning in 1969. Two years later, a pneumacel manufacturing facility was constructed at the Christina Plant. Pneumacel was marketed as carpet cushioning because it showed superior performance. It was also considered for mattress ticking and seat cushion padding. However, production ended in September 1976 because of a recession and the competing demands of other projects for full-scale funding. DuPont retired the equipment and unsold stocks and offered them for sale starting around 1986.

From 1994 to 1996, Fish served as vice president, technology of Synergy Development Corp. in Wilmington, and as an independent consultant. Synergy Development Corp. attempted to purchase the business and resume pneumacel production.

Fish was also a member of the Kennett Pike Association, Inc. He was a vestryman at Christ Church Christiana Hundred, and had avocational interests in airships, steam railroads, antique automobiles, cinema, and photography. The Kennett Pike Association is a residents' and homeowners' association devoted to land use, zoning, development, environmental, and historic preservation issues along the Kennett Pike (Del. 52) corridor and, by extension, the entire northwest quadrant of New Castle County. Fish was a resident of Centerville, a country village and shopping district near the midpoint of Kennett Pike. He died at Wilmington Hospital on April 22, 2009.