Look again. D. microlepis has much finer scales than D. quadrifasciatus, hence the name "microlepis" = small scales. I recall reading somewhere, I believe in the old TFH book Exotic Tropical Fishes, that D. quadrifasciatus has only around 70 scales on the lateral line versus approximately 105 for D. microlepis. Thus, the individual scales on D. quadrifasciatus are about 1 1/2 times the size of those on D. microlepis.
