Kāi yú háng bùguǎn biē shì.

開魚行不管鱉市。

Lit A fish-seller doesn't concern himself with the market [price of] soft-shelled turtles. (pun)

Fig One should not stick one's nose into things which don't concern one.

Note [Note: biē shì, “market (price of) soft-shelled turtles” is a pun on bié (rén de) shì, “other (people's) affairs.”]

Topics pun SELF-RESTRAINT