The idiom "fish in troubled waters" refers to someone who tries to take advantage of a difficult situation or conflict for their own benefit. There are several synonyms that can convey a similar meaning, such as "vulture," "opportunist," and "carpetbagger." A vulture is a bird of prey that feeds on carrion, and the term is often used to describe a person who takes advantage of others in a vulnerable state. An opportunist is someone who takes advantage of any opportunity, regardless of whether it is ethical or moral. Finally, a carpetbagger is someone who seeks personal gain by exploiting a difficult situation, often by being opportunistic or unscrupulous.