Turbellarian black spot disease in bluespine unicornfish Naso unicornis in New Caledonia, caused by the parasitic turbellarian Piscinquilinus sp.

Turbellarian black spot disease is described in a bluespine unicornfish Naso unicornis (Perciformes, Acanthuridae) collected from the wild off Nouméa, New Caledonia, South Pacific. Each cyst contained a whitish worm, 2 to 4 mm in length, which was able to swim freely in seawater. Cyst walls consisted of fibrous tissue with a scattering of melanocytes.