field guide to the freshwater fishes of singapore
Contents

Index of fishes
General parts of a fish
Kelvin K P Lim and Peter K L Ng
  Family Hemirhamphidae
World-wide, marine to freshwater. The surface-dwelling halfbeaks are so-named because the lower jaw is elongated and extends beyond the considerably shorter upper jaw.
close-up photo of head
Head of Hemirhamphodon
showing unequal jaw lengths
Although they are mainly estuarine fishes, a number of species (one in Singapore) do live exclusively in fresh water.

Genus Dermogenys
photo of whole fish, side viewPygmy Halfbeak
Dermogenys pusillus
Ikan Julong, name in chinese characters


Euryhaline; 7 cm; ovoviviparous; carnivorous; gregarious; surface-dwelling. Indigenous, common. Forest and rural streams, reservoirs and mangrove streams.

Males may or may not have a red blotch on the dorsal fin, and as in guppies, the front portion of the anal fin is modified into a gonopodium to facilitate internal fertilisation. Young are also born alive. The males tend to get pugnacious towards one another, and in Thailand, it is used as a kind of "low grade fighting fish". It can be separated from the Forest Halfbeak by its smaller size, and having the dorsal fin beginning just behind that of the anal fin.


Genus Hemirhamphodon
photo of whole fish, side view
Forest Halfbeak
Hemirhamphodon pogonognathus
Ikan Julong, name in chinese characters
Primarily freshwater fish; up to 12 cm; ovoviviparous; carnivorous; gregarious; surface-dwelling. Indigenous, endangered. Forest streams.
This often colourful fish has a fleshy appendage at the end of the lower jaw. The upper jaw is short and curved.

This exclusively freshwater species can be distinguished from the Pygmy Halfbeak by its more slender build and the dorsal fin beginning before the anal fin. The lower jaw is also toothed throughout its entire length.
photo of dorsal fin
Dorsal fin of Hemirhamphodon

photo of dorsal fin
Dorsal fin of Dermogenys
Introduction
Freshwater habitats
Fishes in Singapore
Conservation
Amazing Fishy Facts
About the guidebook
 
From A Guide to Common Freshwater Fishes of Singapore by Kelvin K P Lim and Peter K L Ng
Published by the Singapore Science Centre and sponsored by BP

@Raffles Museum of Biodiversity Research and Singapore Science Centre