Nuculana fragilis has medium-sized shell that is thin, inflated and semipellucid. anterior part is rounded and dorsal margin straight. Exterior sculptured by closely spaced fine concentric ridges. Anterior side of the ligament with 14 teeth. There are 16 teeth in the posterior region. It has beaklike posterior part. Colour: exterior pale brown, interior white with no iridescence. Posterior, dorsal and also ventral margins concave.