Animal Species:Common Silverbiddy, Gerres subfasciatus (Cuvier, 1830)

The Common Silverbiddy has a silver coloured body and highly protrusible jaws. The species occurs in estuaries and on coastal reefs in tropical and warm temperate areas of Australia.

Common Silverbiddy, Gerres subfasciatus

Common Silverbiddy, Gerres subfasciatus
Photographer: Erik Schlögl © Erik Schlögl

Standard Common Name

Common Silverbiddy

Alternative Name/s

Common Silver Belly, Common Silverbelly, Ovate Silverbiddy, Roach, Silver Biddy, Silver-belly, Silverbelly, Silverbiddy, Southern Silverbiddy


The Common Silverbiddy has a silver coloured body and highly protrusible jaws. The dorsal fin is long based. Its anterior spines are black-tipped and are longer than those in the rest of the fin.

Like all fishes in the family Gerreidae, the jaws are highly protrusible. Both jaws can protrude out and down forming a tube. This adaptation to the mouth is used when the fish feeds on bottom-dwelling invertebrates.

Another species of Silver Biddy occurs in southern Australian waters - the Silverbelly Parequula melbournensis. This species is distinguishable from the Common Silverbiddy by its long-based anal fin and by the dorsal fin which is not elevated anteriorly.

Size range

The Common Silverbiddy grows to 20 cm in length.

Similar Species

Silverbelly (see Identification, above)


The species occurs from south-western Western Australia, around the tropical north of the country, and south on the east coast to southern New South Wales.

The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums.  Source: Atlas of Living Australia.

Gerres subfasciatus

Distribution by collection data

Ozcam map of Common Silverbiddy specimens in the Australian Museums.

What does this mean?


It lives in estuaries and on coastal reefs. It is usually observed in schools over sandy bottoms.



What does this mean?


  1. Hoese, D.F., Bray, D.J., Paxton, J.R. & G.R. Allen. 2006. Fishes. In Beesley, P.L. & A. Wells. (eds) Zoological Catalogue of Australia. Volume 35. ABRS & CSIRO Publishing: Australia. parts 1-3, pages 1-2178.
  2. Hutchins, B. & R. Swainston. 1986. Sea Fishes of Southern Australia. Complete Field Guide for Anglers and Divers. Swainston Publishing. Pp. 180. (as Roach)
  3. Kuiter, R.H. 1996. Guide to Sea Fishes of Australia. New Holland. Pp. 433.
  4. Kuiter, R.H. 2000. Coastal Fishes of South-eastern Australia. Gary Allen. Pp. 437.
  5. Yearsley, G.K., Last, P.R. & R.D. Ward. 1999. Australian Seafood Handbook, an identification guide to domestic species. CSIRO Marine Research. Pp. 461.


Mark McGrouther , Senior Fellow
Last Updated:

Tags fishes, ichthyology, Silver Biddy, Gerres subfasciatus, Gerriidae, Common Silverbiddy, silver, protrusible jaw, estuaries, coastal reef, tropical water, temperate water, marine, Common Silver Belly, Common Silverbel, Ovate Silverbiddy, Roach, Silver-belly, Silverbelly, Silverbiddy, Southern Silverbiddy, 10 cm - 30 cm,