The surface area of two closely related mudfish species have been determined by coating the animals with masking tape. The results indicate thatLabeo capensisspecimens above 95 g body weight have a larger surface area than correspondingL. umbratusanimals. The same is true for the fin surface area above 50 g body weight. Below these weightsL. umbratusspecimens have higher surface areas. The body surface area ofL. capensisis always lower than that ofL. umbratusin the range studied.