The top photo looks great! He's a beautiful blue color. The dark head is normal.
Often, they're pale at the store. When you get them home, and put them into clean warm water, and feed them good food, they usually "color up," meaning that their true colors come out.
The white growth on his pectoral (front) fins is also good! It indicates new growth. This is another sign that he's healthy and still growing.
He looks great to me. The fish in the top photo looks much healthier to me than the one in the bottom photo. So you're doing a great job with him.