Hi, I just signed up. I am trying to create a pet, but for some gosh darn reason I can't manually change the colors of the pet. I can click random and hope I get something close to what I want. But for the life of me I can't change the colors manually. It let me do so on my Avatar, but not my pet. So frustrating and confusing.

Says I can create my first pet however I want, yet it won't let me change colors.... Maybe I'm missing something. And refreshing browser doesn't help as it resets my progress.

If you've already created the pet, the colors cannot change without a pet dye. This can be purchased with scales, a currency you get by nurturing pets.
However, since the pet is already generated, you won't be able to change it without that item, therefore keeping Desvious at its current state until the pet dye is used.