I have no experience with the color red but I tend to doubt that it will be as effective since blue and white are predominately better attractive colors. If you have a red barrel, try it and let me know how it works for you!Please watch video number 2 (kzfaq.info/get/bejne/psiIit1-qK2uoH0.html) you can see the effectiveness of the fly paper. I think I would increase the fly paper rings to six for smaller things like gnats. Best wishes and please share your successes.