albinos and pieds are known for being problematic feeders more so than others, you kinda just have to take your lumps with it, usually around 500 - 700 grams is when they usually start to act up. i have a 4 year old female that is still only 600 grams, what are you feeding? i would try a live mouse hopper or african and see what happens, also (he is a bit young for this) do you cool down your collection in the winter for breeding ? If so and he is in the same rack then he may just be doing what comes natural to them and slowing down for breeding season, but usually they will eat through their first winter.