My dog is afraid of his reflection, any suggestions?

[mfleshner]

6 months ago I rescued a 3 year old pit bull from animal control. He is incredibly gentle and loving. He doesn't bark, except at his own reflection. In fact, he is so fearful of his reflection that he will no longer go in a room that he will see his reflection. However, he isn't afraid of other dogs. He is fine with my brother's dog, the neighbor's dog, etc. This doesn't make any sense to me. I hate to see him so afraid. Any ideas?

Thanks in advance!