The Vietnamese term "cá nước" directly translates to "fish and water" in English. This phrase represents a close relationship, often used metaphorically to describe the deep bond between two entities, especially in the context of the relationship between the people and the army in Vietnam.
In a more advanced context, "cá nước" can be used to reflect on historical events, national unity, or discussions about governance and social responsibility. It emphasizes how the welfare of one group (the fish) is intertwined with the conditions and support provided by another (the water).
There aren't direct variants of "cá nước," but you might encounter phrases like "tình quân dân" (the relationship between the army and the people) that convey similar meanings.
While "cá nước" primarily refers to the relationship between people and their military in a metaphorical sense, it can also be interpreted more broadly to reflect any relationship that is symbiotic or interdependent.