Interesting coincidence, now that he's written the Raw Shark Texts screenplay - in 1993, Simon Beaufoy co-directed and co-wrote the short "Physics for Fish" for the TV show 10x10:

"Anna, aged 15, is preoccupied with next week's physics exam. Mark, aged 25, is preoccupied with catching a 30-pound pike and with getting Anna into bed. When the exam comes, Anna is faced with a question about refraction of light in water, illustrated with a diagram of an angler. All she can think of is Mike, waiting for her. Meanwhile, she herself is turning into a fish." (Source: BFI.org.uk)

Beaufoy does seem to keep coming back to fish and water - in his interview (MP3) with Creative Screenwriting magazine he says he lives on a boat, and according to The Telegraph he's also written an adaption of Salmon Fishing in the Yemen by Paul Torday:

"Torday's debut melds sharp satire with a meditation on the transforming power of belief in a story of a wealthy Yemeni sheikh who wants to perform a miracle and introduce salmon into the inhospitable climate of his ancestral land, aided by a British prime minister in need of a good news story after too many foreign wars."