New records of four reef fish species for Hong Kong

Background A total of four reef fish species: Amblyeleotris japonica, Halichoeres hartzfeldii, Canthigaster papua and a Parapriacanthus species, are reported for the first time in Hong Kong. Methods The specimens were discovered during underwater reef fish surveys. About 20 individuals of one Parapricanthus species were found at Tai Chau. A single Amblyeleotris japonica and a single Halichoeres hartzfeldii were both observed at the west coast of north Ninepin Island. One individual of Canthigaster papua was found at Clearwater Bay. Results The likelihood of these four species having been artificially introduced into Hong Kong waters is discussed and eliminated. Comparison of these four species is made against six other species previously encountered in Hong Kong waters that were not already documented in local records and suspected to be artificially introduced. Conclusions Four reef fish species, including Amblyeleotris japonica, Halichoeres hartzfeldii, Canthigaster papua and a Parapriacanthus species, are reported for the first time in Hong Kong. Details on the sighting records, locations, habitats and behavior of the observed individuals are described. The validity of the natural origin of these fish is discussed.