Cynthia Fish (left) and John Fish pose in this undated handout photo. Photo courtesy of Tabor Academy

A private seaside boarding school on the South Coast is the recipient of a $10 million gift from construction magnate John Fish and his wife Cynthia Fish.

Fish, the CEO of massive Boston construction company Suffolk, graduated from Tabor Academy in 1978, the school said.

The gift is the largest single one in the Marion school’s 148-year history, but it comes on top of around $20 million in total donations from the couple over the last 40 years that have helped resurface some of the school’s playing fields, among other initiatives.

“We are deeply grateful to John and Cyndy for this inspirational gift that will allow us to change lives in profound and transformational ways at Tabor,” head of school Tony Jaccaci said in a statement. ” John and Cyndy live the values of our school, and this generosity is a testament to their commitment to connect, serve and lead.  A gift of this magnitude will make a deep difference in providing the best education possible for our students and I know will motivate others to support as well.”

The gift will be used to enhance professional development opportunities for staff, bolster coaching and training for the school’s athletic programs and build out financial aid programs.