Will fishing line rot outdoors?

My granddaughter loves the mirrored line I have twinkling in the birch tree. My sis in law said it won't last long because it is fishing line. I figured plastic line would do well - I liked the invisibility of it. Didn't think it would rot. Will it??. Recommendations? This is just for a long string of small mirrors back to back with plastic fishing line sandwiched between. Thanks