Hmm.. weird my black horse never gets sunbleached, but if you really don't want it you could move him away from direct sunlight to a place with more shade. He would probably enjoy getting out of the sun anyways! Also you could buy a tail wrap and braid that in, but you couldn't really do anything about the mane. Also a fly sheet might work to reflect some of the direct sun. Or.. keep him out of the sun completly when the sun shines the hardest.