In Harry Potter, there is only the one Basilisk, as far as we know. The one in "Harry Potter and the Chamber of Secrets" is the same one that Ron and Hermione see during the Battle of Hogwarts in "Harry Potter and the Deathly Hallows." This is most likely the case, because earlier in the book Ron, Harry and Hermione were talking about how only extremely powerfully magical objects could destroy a Horcrux, and the venom in the Basilisk's fang is just that: extremely powerfully magical.

In Harry Potter, there is only one Basilisk as far as we know. The one in "Harry Potter and the Chamber of Secrets" is the same one that Ron and Hermione see during the Battle of Hogwarts in "Harry Potter and the Deathly Hallows." This is most likely the case, because earlier in that same book Ron, Harry and Hermione were talking about how only extremely powerful magical objects could destroy a Horcrux and the venom in the Basilisk's fang is just that: extremely powerful and magical.