Hi there! ^_^
Welcome to Rescreatu! I'm Cat.
So to answer your question, you would have to view the creatu page, located in a link inside the hatchery. You can hatch the colors natural-albino, the others can be colored with dye kits. Dye kits are in the black market, located on Reiflem, they are usually expensive so you'd have to save for a while. You can also buy natural colored jellybeans through the credit shop for either $10.00 USD or with 10,000,000 tu. Once those are fed to a pet, it randomly changes their color, the only colors that can be gotten with a natural colored jellybean are those natural through albino.
Hope this helps~
Feel free to ask or mail me if you have further questions.