Well it was the guy I responded to who brought up veganisim as a solution in his top level post, but okay let's talk overpopulation. Axolotl have only ever been known to live in a few lakes which have almost entirely been obliterated by Mexico City, home to 10 million people. What exactly do you propose? Even if the population replacement rate in Mexico City were brought below 1, how many years would it take to depopulate the city? Short of forcing people out of the city at gunpoint (and to where, exactly?) how could you actually get the city depopulated in a reasonable amount of time to save the axolotl who might have a few years left at most? And how would this undo the habitat destruction which already occurred? How would you remove the structure of the city and restore the environment which it replaced decades+ ago?