Yǒurén shuō pángxiè hé shìzi xiāngkè, qíshí méi kēxué yījù.
Some say crab and persimmon don't go together, but there's no scientific basis.
Tips
culture
相克 pairs with its opposite 相生 (mutually generating) in Five Elements (五行) theory: 金生水, 水生木... and 金克木, 木克土.... In modern usage it also covers food taboos, zodiac pairings for marriage, and personality clashes.
