The Axolotl is a rare type of salamander, closely related to the Tiger Salamander species. They are about 9 inches long on average, and carnivorous. The cute critters are only native to central Mexico's Lake Xochomilco, and yes - they are edible, and used to be a staple in the Aztec diet; but they are highly endangered due to the expansion of Mexico City.
They are, on the other hand, highly bred in captivity due to their value in research.
Axolotls are especially easy to breed compared to other salamanders in their family, which are almost never captive bred due to the demands of terrestrial life. One attractive feature for research is the large and easily manipulated embryo, which allows viewing of the full development of a vertebrate. Axolotls are used in heart defect studies due to the presence of a mutant gene that causes heart failure in embryos.