Pseudanthias bartlettorum has a somewhat elongated, moderately compressed body which is around 3 times as long (in standard length as it is deep. The males have a thickened upper lip which is a little pointed and can be moved up and down. It has a moderately large, obliquely angled mouth in which the maxilla extends to the rear edge of the eye. On females the mouth is terminal but the thickening of the upper lip causes the mouth to slightly point downwards. The lateral line is curved and follows the curve of the dorsal profile.[3] The dorsal fin has 10 spines and 17-18 soft rays while the anal fin has 3 spines and 7 soft rays.[2] The upper two fifths of the head and body are bright yellow and the remainder of the body is lavender, fading on the fish's underside. The portion of the head behind the eye is lavender becoming whitish ventrally. There is a dark orange band on the head which runs from the snout to the lower part of the eye before fading behind the eye. The iris is dark orange. The dorsal fin is yellow with the first two spines and the tips of the other spines being lavender and the anal fin is pale lavender with a reddish margin at the front. The caudal fin is yellow, brighter on the lobes with violet outer margins. The pectoral fins are hyaline and the pelvic fins are pale lavender.[3] It grows to a maximum standard length of 9 centimetres (3.5 in).[2]
