Otherwise, I love how well he's keeping his colors,
What is his weight? He may just be a slow grower; they all grow at their own speed. I have two males hatched a month apart; one weighs 1000 grams and their other is 1300 grams and much longer.
1.0 Trick Pinstripe (Loki)
0.1 Firefly Axanthic (Oreo)
1.0 VPI Black Satin Black Pastel (Sneaky)
1.0 Pied (Spot)
0.1 Normal (Fatty)
0.1 Bumblebee (Bumble)
1.0 Pastel Genetic Stripe. (Ozzy)