Axolotls
Axolotls (Ambystoma mexicanum) are originally from Mexico, but in the late 19th century were introduced to America as pets. Their native habitat is Lake Xochimilco, which maintains a temperature of no more than 68°F, which is why it is essential that their water tank remains between 59°–65°F. A pet axolotl's diet mainly consists of worms, particularly earthworms, as they contain most of the protein and nutrients the axolotl needs. They can also be fed sinking pellets, though these should be fed in moderation. While the wild axolotl is generally dark colored, pet axolotls come in a variety of colors - pink, black, yellow, etc.
Don't worry if your pet seems to be inactive during the day. Axolotls are most active at night and during the early hours of the morning, so you will be able to observe them swimming and exploring at those times. Take note of your axolotl's color, and if your pet is paler than normal, it may mean that your axolotl is not happy or is under considerable stress. When there is change in an axolotl's color, you should check all of the water parameters to make sure the water is at the correct temperature and that the ammonia and nitrite levels are adequate. It is generally recommended that only a single axolotls is kept per tank as they will often fight when not given enough food and/or space. Adding fish to the tank is not recommended either, as fish tend to stress axolotls by nibbling on the axolotl's gills. You will typically see an axolotl flaps its gills at different speeds, which means they are obtaining oxygen from the water; when more oxygen is required, you might observe their mouth open. An axolotl does not have clear eyesight, and its vision is especially poor in bright light; bright lights will instantly make it retreat into any shade it can find. Even though its vision is poor, a hungry axolotl will track and even lunge towards any movement it detects; this is a very clear sign you must feed your pet. A relaxed axolotl will typically lazily float across its tank, so take this is a sign you are doing a great job with your pet!