If you just mean it's too white, go to the ship costume editor at ESD and set it to hull type 4. If you mean the hull markings, you can change the colors of them there as well, or disable the markings entirely under Advanced by setting all the Pattern options to None.
I wouldn't call any options you can get there fluorescent, though, which brings me to the next question: What shield are you using? The AEGIS and Reman shields could both be described as fluorescent. You can right click on items like that and click Disable Visuals to get your base hull back.