Is the fixture controlled by 2 switches?
While the red wire is still disconnected, is there anything else in the area that doesn't work properly?

It isnt connected to 2 switches. I have not connected anything back to the wires so I am not sure what was connected to the red wire to bein with. I do know that the old light fixture had an electric outlet as part of the fixture. Maybe the red wire was connected to that?

First always assume that a wire is hot until proven otherwise. So be careful. I would suggest (With the breaker shut off) take your light switch cover off and look in and see if the red wire is there. If so is it connected to anything? If not simply wire nut it and place out of way. If it is then you need to see what it is connected to. If it is connected with the Black wire at switch then the red is hot and could have been for the outlet on light fixture or maybe a vent fan? If you can't find the other end call an electrician and have him locate and fix. As a loose hot wire can be deadly. Good luck hope this helped.

If there are no other wires in the box it is probably extra for a possible fan. Connect the black and white to the light and cap the red. If the light doesn't work cap the black and connect the red to the light.