BP Losing Weight

Hi,
I got a Ball Python near the end of May this year, and so far he has been a wonderful eater. He doesn't miss a meal and loves eating. Recently, I've noticed that he's lost weight. He's starting to get that kinda triangle look to him. He's not skinny yet, but he is losing weight and it's worrying me. He's been eating every time I offer him food, and since he's still young, that's about every 6 days. I feed him small mice. His cage setup hasn't changed at all since I got him, and he just shed less then a week ago. Any ideas as to what's happening?

By small mice how small do you mean?

How big is your snake?

Because he has a triangle look does not mean he lost weight it's more likely that the proportions are changing, he is getting longer but is not likely fed enough to keep a plump look.

Honestly by now a snake acquired at the end of may should be on something larger than small mice.

There are 2 common mistakes with BP, hatchlings who have high metabolism and grow quickly are underfed and adult who are the opposite are overfed.

Until the snake is about 500 grams you should offer a prey equal the girth size.

Hi,
He is still a pretty small snake. I should've clarified better, he is being fed small adult mice. I've actually wondered if they were too big for a while but they are about the size of him at his largest girth. He was a pretty good weight looks wise when I got him, I suppose he could just be getting longer which makes up for the looks of being skinnier. He does get a small adult mouse every 5-6 days..

Ok how big is the snake?

Unfortunately I don't know his weight, I did order a scale online a few days ago as I couldn't find one in my town. He is 23 inches long.