fish in troubled waters

Translations
ловить рыбу в мутной воде
He's always fishing in troubled waters, trying to gain from other people's problems.
Он всегда ловит рыбу в мутной воде, пытаясь извлечь выгоду из чужих проблем.
Definitions
To try to gain an advantage or profit from a chaotic, difficult, or confusing situation, often by taking advantage of others' problems or the disorder present.