I adopted a 25yo male M2 about a month ago. This is his 3rd home(at least) and he was previously abused my a male. Peaches has been very friendly and easy to handle up until about 3 days ago. It started when I asked him to step up (which is has been very good at). He hissed and turned his back on me, so I closed the cage and left him alone. Every few hours I would come back and try again, and I would get the same response. Then, on my last try, he lunged at me! And ever since then, he has been lunging at me through the cage when I walk by.
What could be causing such a drastic change? Any help or advice would we wonderful!