[alpacassei]

That sounds like cage or food aggression tbh. What size cage is he in? Its most often caused by being in a smaller cage as it makes them become more territorial of their environment.

Ive only ever dealt with cage aggression in Russians so hopefully someone with more experienced in Syrians will comment soon since Russian and Syrian behaviour is very different.

Generally with Russians it’s something that fades over time as your hamster becomes more trusting of you. With my current cage aggressive ham Flurry, I have her climb into a hide and then lift her out before spot cleaning. I scatter feed when she’s asleep otherwise she tries to charge at my hands.

I have a strawberry hide thats used only for taking her out the cage so she know if the hide is in her cage and she climbs into it, its time for her to come out and play.