Idiom for opportunistically exploiting a situation to one's advantage

Solution 1:

Interestingly, English has almost the same expression: "fishing in troubled waters", going back to at least the 16th century.

It seems to originate in a belief among fishermen that fish rise to the surface in foul weather and may be more readily netted—hence the phrase "mackerel gale", a storm which promises a good catch.

But very early it was applied figuratively to just such situations as yours. Grafton's Chronicle and Foxe's Actes & Monuments (both 1569) quote a letter from Pope Innocent III warning King John of England not to trust those who advise him to dispute the authority of the Church:

Settle not yourself to obey their persuasions, which always desire your unquietness, whereby they may fish the better in the water when it is troubled.

I have not yet found their source for this; if authentic, it takes the phrase back to 1208 and, presumably, in Latin.

Solution 2:

You can consider:

• When life gives you lemons, make lemonade (related)
• Seeing opportunity in calamity (The Churchill attribution is apparently erroneous.)

• Come out smelling of roses:

  if you come out smelling of roses, people believe you are good and honest after a difficult situation which could have made you seem bad or dishonest

  There was a major fraud investigation, but Smith still came out smelling of roses.

There are variants for all of the above and are also adapted as necessary. For example, the first phrase could be adapted to "making lemonade from lemons". This would be understood by most readers familiar with the saying.