Your answer is ambiguous, would you care to explain in more depth?
You firstly stated that: "It's a Hindu belief/practice and not taught in Buddhism"
Buddhism being the key word here for misunderstanding. Do you mean theravada buddhism specifically? For the obvious reasons that such views ARE taught in different understandings, labelled or imputed as Buddhism!
Then another question:
"Is the story of the naga king "---- "No, it's not considered as symbolism"
As if the existance of nagas and a race of such beings being able to ellect (or be conquered) by such rulers "do" exist in conventional reality, not just as a fable for those with lesser proclivies for the dept of understanding the truths