In Neopia, pets have different colours. They come in the standard, basic colors: red, yellow, green and blue. Because it is one of the basic colours, all pet species can be yellow. A pet can become yellow through the use of a magical paint brush or, for some species, a magical Morphing Potion.
Other ways to get a yellow pet:
*Note: Magical plushies or morphing potions will also change the pet's species.
You can see an example of a yellow neopet below.