Black paint would be difficult to get a decent finish with
Just one of those things. Gloss black shows every defect, every run. every dust partical and every brushstroke. Not something I`d recommend to anyone with no experience painting and a color thats best sprayed anyway.
As an alternative, in the automotive section of the large hardware stores where I live, its possible to buy reflective tape in 10ft rolls in red, yellow, blue, white and (believe it or not) BLACK.
The stuff is about 2 inches wide and so may not cover the fender completely, but maybe a silver accent down the sided would look pretty good anyway.
This is a peel off / self adhesive product that works best if the surface is cleaned with alcohol, but its extremely durable. In fact its very difficult to get off once installed. I`ve used this on bicycles and snowboards and the preliminary applications are all over 12 years old and still look as good as new.
Cost is about $8 and cuts with sissors or a razorblade and straightedge.