Part of Speech: Noun
In more advanced discussions about marine biology or fishing, you might mention the ecological role of sergeant fish in their habitat or how they are sought after by sport fishermen due to their size and fighting ability when caught.
While "sergeant fish" primarily refers to this specific type of fish, it does not have other common meanings in English.
There are no common idioms or phrasal verbs specifically associated with "sergeant fish." However, if discussing fishing in general, you might hear phrases like "casting a line" (to start fishing) or "reel in" (to pull a fish in when it bites).
In summary, "sergeant fish" is a noun that describes a specific type of striped tropical fish found in warm waters.