This is an axolotl.
Axolotls typically reach 6-9 inches in length and live 10-15. (A captive specimen in Paris is said to have lived for 25 years.) They are closely related to Tiger Salamanders, but unlike their cousins axolotls do not metamorphosize into land dwellers. Metamorphic failure is apparently caused by a lack of thyroid stimulating hormone, which triggers the transformation in other salamanders. Interestingly, if injected with iodine axolotls will indeed metamorphosize, although they will scarcely live five years if they do. (They have been known to metamorphosize in the wild, but this is extremely rare.)
They used to be found in Lake Chalco in central Mexico, but that lake no longer exists: it was artificially drained to avoid periodic flooding that adversely affected nearby populations of a species of ape, homo sapiens. Now wild axolotls can be found only in Lake Xochimilco near Mexico City, and they are a critically endangered species:
Populations are in decline as the demands of nearby Mexico City have led to the draining and contamination of much of the waters of the Xochimilco Lake complex. They are also popular in the aquarium trade, and roasted axolotl is considered a delicacy in Mexico, further shrinking their numbers.
Awww! I will totally give an axolotl a good home! I want a pink one! No, wait! — I want a black one! A black one! And I will not roast him and eat him! (Unless I get really, really hungry!)
Axolotls can regenerate entire lost limbs and other organs. Some have been found to regenerate lost parts of their brains — which makes them an excellent model organism for the Palace research program into a cure for Conservative Personality Disorder. No?