As with other species of Aegires, the skin is toughened with tiny spicules, the upper surface has a few irregular pustules, and the small rhinophores are smooth and simple. The branched gills are situated midway along the body, partially hidden by three large lobes. The animal has a yellow background colour, with a pattern of diagonal and transverse black lines arranged in a network over the entire body. The gills and rhinophores are essentially yellow, but in juveniles, and some adults, there can be some black pigmentation. Notodoris minor can grow to 14 cm in length.
Notodoris minor feeds on calcareous sponges belonging to the family Leucettidae. On the Great Barrier Reef it has been found feeding on the calcareous sponge Pericharax heterographis and Gosliner et al. (1996) have recorded it eating Leucetta primigenia elsewhere in the Indo-West Pacific. It is often found on coral substrates, but its distribution is dependent on the presence of its food sponges. It has been found from 3 to 24 m in depth.