My Fishes Birthmark

My goldfish has a special birthmark. As you can see it's heart shaped. Dern found it because we were looking at the new background that he bought for our fish tank. He showed it to us and what is weird is that fish started out as only black with a tiny bit or orange, and now he's totally white. That shows that gold fish change colors. My brother told me that they change colors depending on the kind of food you give them. We just thought it was interesting and that we'd share it with you.