Obviously these are not as bright or as colorful as the Xudarian post, but in my imagination, I’m thinking that Astonians just don’t have the color range that other species have. So the darkest shade that an Astonian comes in is like a cappuccino color while the lightest is white. The real variation that I’m thinkin’ comes from the skin lines and the tail. Some of them have lines all over the place while some barely have any lines at all. Some tails are fat and bumpy while others may be thin and smooth, with many in between. The longer the tail, the older you are. Some tails can curl, some are long enough to wrap around the neck.
But my favorite headcanon is that the really, really old Astonians are short and squishy. They’re born that way, and they eventually end up that way. XD Old!Walker would probably be the cutest of them all!