Coloration is variable among populations. Generally, the body and tail are dark brown dorsally, sometimes with olive hues. This background is broken by irregular lighter mottling (light brown, cream, or slightly orange). Day and night coloration differ: at night, the body appears paler, and the posterior half of the tail becomes distinctly black; during the day, this contrast is reduced or may disappear entirely. In some populations, mottling transitions into a marbled pattern on the lower flanks and proximal tail. No conspicuous clusters of iridocytes are present dorsally or laterally. Pigmentation of the trunk continues seamlessly onto the muscular part of the tail. The tail musculature and fins are darkly mottled (paler during daytime), sometimes with an orange tint, and often bear irregular clusters of iridocytes. The ventral body surface is opaque white with dense stippling of small melanocytes; gills and gut are not visible through the skin. The oral disc also bears scattered melanocyte stippling.