So about a month ago I bought a 7 year old green cheek conure from a friend of my roommate and I've been having some issues. I am relatively new to birds but my roommate who is fairly experienced and has a caique of her own has been helping me. Dexter, what I've been calling my green cheek, seemed to be very sweet and curious for the first 2 days we had him and then all of a sudden became very aggressive, both in and outside of the cage. We thought he would settle down, because he did come from a home with 2 high energy pitbulls, but he did not. At first he was only aggressive while inside the cage and now just lunges if I come anywhere near him unless I have a treat. However, he seems to get bored of the treats fairly quickly and at times decides to stop eating them and instead lunge for my fingers. He draws blood when he bites. Also, he is blind in his left eye, but I always approach him from the right so as not to startle him. As someone relatively inexperienced with the species, any tips/insight regarding how to gain his trust etc. would be wonderful. Thanks!