Tortoise is a recognized color. According to dutchrabbit.com, color is to be a bright, clean orange, blending into smokey-blue shading over the lower rump, and carrying well down the haunches. The top color should carry down into the under color, blending into a dark cream color next to the skin. Upper portion of tail color should match top body color. The shadings on the head should be the darkest at the whisker bed, blending into lighter shadings on the jaws, darkening again at the ear base, and blending up the ears to match body color. The smoky blue shading is to include the underside of the tail. Eyes to be Dark Brown. Faults include white hairs, smut or smudge, throughout the orange color, lack of bold shadings, underside of tail light in color. Disqualifications include the absence of shadings.
They also come in Black, Blue, Chocolate, Steel, and Gray.