Dongsha Atoll National Park has recorded the world’s smallest coral reef fish species—Trimmatom nanus—as a new species record for Taiwan. This tiny goby is extremely small, with mature females measuring approximately 9 mm in length and a maximum body length not exceeding 10 mm. It is a benthic coral reef species that was previously known only from the western Indian Ocean and the central-western Pacific region. The species was discovered during a diving survey at the outer Dongsha Atoll by a research team led by Professor Yi-Hsiung Chen of National Taiwan Ocean University. This finding also represents the northernmost distribution record of the species worldwide.

　　The waters surrounding Dongsha Atoll feature rich and diverse habitats. Since 1995, a total of 679 fish species have been identified and recorded, including 78 species in the family Gobiidae. The discovery of Trimmatom nanus as a new record species further demonstrates that the waters around Dongsha Island still harbor abundant and significant fish biodiversity.

　　In recent years, global climate change—particularly ocean warming and the impact of typhoons—has directly affected the marine habitats of Dongsha Atoll National Park, causing coral reef mortality and substrate disturbance. Small benthic fish species are highly dependent on the seabed substrate. Changes in their species diversity not only directly reflect habitat integrity but can also serve as important indicators for marine ecosystem management and conservation. For more information, please visit the Marine Conservation section of this website under Ecological Conservation and Marine Knowledge.
 

Figure 1. The world’s smallest coral reef benthic fish – Trimmatom nanus / Photo by Yi-Hsiung Chen	Figure 2. Seascape of the outer reef area of Dongsha Atoll / Photo by Yi-Hsiung Chen