From TikTok to McDonald’s Happy Meals, Mexico’s ancient axolotl is everywhere, except where it is supposed to be—in the wild.

Synthetic dyes used to make brightly colored cereals, drinks and candies are coming under scrutiny in states across the country.

The two are pleading with immigration authorities to release González on humanitarian parole to donate the kidney. “After that, I will return to Venezuela,” González said from a call in the detention ...