Smiling Goby, Mahidolia mystacina (Valenciennes 1837)

Other Names: Flagfin Prawngoby, Flagfin Shrimpgoby

A Smiling Goby, Mahidolia mystacina, on the northeast coast of Lizard Island, Great Barrier Reef, Queensland, depth 24 m. Source: Lyle Vail / Lizard Island Field Guide, License: CC by Attribution-NonCommercial-ShareAlike

A pale grey to yellowish or dark brown shrimpgoby with six diagonal brown bands, orange spots and lines on the head, and dark bands and/or one or more blue to black spots on the first dorsal fin. The coloration and shape of the first dorsal fin is highly variable.

Cite this page as:
Bray, D.J. 2019, Mahidolia mystacina in Fishes of Australia, accessed 08 Dec 2022,

Smiling Goby, Mahidolia mystacina (Valenciennes 1837)

More Info


Recorded in Australia from Darwin, Northern Territory, to Cape Ferguson, Queensland. Elsewhere the species occurs in the tropical, Indo-west-central Pacific.

Inhabits silty and muddy areas in estuaries, mangroves, the lower reaches of rivers and on coastal reefs.


Thacker et al. (2011) found evidence of potential cryptic species within the current understanding of Mahidolia mystacina.


The specific name mystacinus is from the Greek mystax meaning 'upper lip', and the Latin inus meaning 'belonging to'.

Species Citation

Gobius mystacinus Valenciennes, 1837, Hist. Nat. Poiss. 12: 124. Type locality: Java.


Bray, D.J. 2019


Atlas of Living Australia

Smiling Goby, Mahidolia mystacina (Valenciennes 1837)


Allen, G.R. & Erdmann, M.V. 2012. Reef fishes of the East Indies. Perth : Tropical Reef Research 3 vols, 1260 pp.

Hoese, D.F. 1986. Family No. 240: Gobiidae. pp. 774-807 figs in Smith, M.M. & Heemstra, P.C. (eds). Smith's Sea Fishes. Johannesburg : Macmillan South Africa xx + 1047 pp. 144 pls.

Kuiter, R.H. 1992. Tropical Reef-Fishes of the Western Pacific, Indonesia and Adjacent Waters. Jakarta : PT Gramedia Pustaka Utama 314 pp. pls.

Kuiter, R.H. 1996. Guide to Sea Fishes of Australia. A comprehensive reference for divers and fishermen. Sydney, NSW, Australia : New Holland Publishers xvii, 434 pp.

Larson, H. 2016. Mahidolia mystacina. The IUCN Red List of Threatened Species 2016: e.T192982A2180744. Downloaded on 21 August 2019.

Larson, H.K. & Lim, K.K.P. 2005. A guide to the gobies of Singapore. Singapore : Singapore Science Centre 164 pp.

Larson, H.K. & Williams, R.S. 1997. Darwin Harbour fishes: a survey and annotated checklist. pp. 339-380 in Hanley, H.R., Caswell, G., Megirian, D. & Larson, H.K. (eds). The Marine Flora and Fauna of Darwin Harbour, Northern Territory, Australia. Proceedings of the Sixth International Marine Biology Workshop. Darwin : Museum and Art Gallery of the Northern Territory 466 pp.

Macleay, W.J. 1878. The fishes of Port Darwin. Proceedings of the Linnean Society of New South Wales 1 2(4): 344-367 pls 7-10

Myers, R.F. 1999. Micronesian Reef Fishes. A comprehensive guide to the coral reef fishes of Micronesia. Guam : Coral Graphics vi 330 pp. 192 pls.

Randall, J.E. 2005. Reef and shore fishes of the South Pacific. New Caledonia to Tahiti and the Pitcairn Islands. Honolulu : University of Hawaii Press 707 pp.

Smith, H.M. 1941. The gobies Waitea and Mahidolia. Journal of the Washington Academy of Sciences 31(9): 409-415 figs 1-2

Thacker, C.E., Thompson, A.R. & Roje, D.M. 2011. Phylogeny and evolution of Indo-Pacific shrimp-associated gobies (Gobiiformes: Gobiidae). Molecular Phylogenetics and Evolution 59: 168-176. 
Valenciennes, A. in Cuvier, G.L. & Valenciennes, A. 1837. Histoire Naturelle des Poissons. Paris : Levrault Vol. 12 507 pp. pls 344-368.

Yanagisawa, Y. 1978. Studies on the interspecific relationship between gobiid fish and snapping shrimp. I. Gobiid fishes associated with snapping shrimps in Japan. Publications of the Seto Marine Biological Laboratory 24(4/6): 269-325 figs 1-23 pls 1-3

Quick Facts

CAAB Code:37428188

Behaviour:Shares burrow with alpheid shrimps

Conservation:IUCN Least Concern

Depth:5-25 m

Fishing:Aquarium fish (rare)

Habitat:Reef associated, silty bottoms

Max Size:8 cm TL

Species Image Gallery

Species Maps

CAAB distribution map