The eastern subspecies, "F. d. diaphanus", can be differentiated from the western subspecies, "F. d. menona", by the presence of a further anterior dorsal fin position, increased number of anterior bars in the males of the subspecies (9-15 compared to 5-0 for "F. d. menona") with more intense bars along the side that stay intact along the anterior back, a higher number of scale rows (40-44 "F. d. menona", 45-49 "F. d. diaphanus"), and a combined number of dorsal and anal fin rays totaling 24-26, compared to 23-24 for "F. d. menona". Larger maximum sizes have been reported for "F. d. diaphanus" than "F. d. menona".