What is an attractive way to prevent a small dog from slipping through the bars of a wrought iron fence?

My chihuahua can slip through the bars of our wrought iron fence and escape onto the street. We would prefer not to put chicken wire up around the yard in order to contain him which would really diminish the attractiveness of our yard. We are unsure of what would be a better alternative. Our fence is a light beige color. I have heard of electronic dog fencing, however, that appears to be pretty expensive. I'd love a more economical, but attractive alternative. Any suggestions?