We've all seen stunning examples of biotope aquariums that attempt to replicate a slice of a freshwater environment many of us can only dream of viewing in person. Some of us devote time, energy, and money into keeping and maintaining say, an Amazonian stream with discus, tetras, and corydoras, or an African rift lake full of cichlids and catfish, or a Borneo peat swamp with rasboras and loaches.
However, what about freshwater environments found in Singapore? While our freshwater fish diversity is just a fraction of that found in neighbouring countries, we do have a variety of habitats that we can attempt to recreate.
For most of Singapore's history, our freshwater environments were dominated by rainforest streams and freshwater swamp forest. With settlement by people, we get rural streams flowing through agricultural land, as well as a mixture of rice paddies and ponds for aquaculture. The British colonists created lakes in the form of reservoirs. With the modernisation and urbanisation of Singapore, we get even more reservoirs (many formed by damming up river estuaries), ponds and lakes in our parks, as well as concrete canals and drains.
From our reservoirs and shaded pools in swamp forest, to sunlit streams in open country and urban ponds overgrown with algae and duckweed, and even concrete monsoon canals, many of our native fishes have adapted to survive in these ecosystems. There are many possibilities, not to mention the fact that we also have a large number of introduced and non-native fish species (which I'll cover in another post).
This thread here is meant to be a checklist of fish species found in freshwater environments in Singapore, with this first post covering the native species. Many of the native fishes present in Singapore are featured in the aquarium trade, although they are likely to be of Malaysian or Indonesian ancestry. Unfortunately, many of our native fishes are restricted to rainforest or swamp forest streams in our nature reserves, where they are threatened by habitat destruction, as well as the potential impact of introduced species. Some of them have not been seen for many years, and are thought to be extinct, although it is some consolation that we do not have any endemic freshwater fishes, and that the endangered and extinct species are still present in neighbouring countries.
I have tried as far as possible to cover only those species known to breed entirely in a freshwater environment, which omits those species that can live in freshwater for some time, but require brackish or marine conditions to breed.
Dwarf rasbora (Boraras maculatus)
Chemperas (Cyclocheilichthys apogon)
Porthole rasbora (Rasbora cephalotaenia)
Einthoven's rasbora (Rasbora einthovenii)
Two-spot rasbora (Rasbora elegans)
Largescaled rasbora (Rasbora paucisqualis)* (Extinct?)
Saddle barb (Systomus banksi)**
Clown barb (Systomus dunckeri) (Extinct)
Six-banded barb (Systomus hexazona)***
Spanner barb (Systomus lateristriga)
Harlequin rasbora (Trigonostigma heteromorpha)
* Listed in older sources as Banka rasbora (Rasbora bankanensis)
** Listed in older sources as Two-spot barb (Puntius binotatus)
*** Listed in older sources as Puntius johorensis
Grey-banded Loach (Nemacheilus selangoricus)
Half-banded coolie loach (Pangio semicincta) (Extinct?)
Spotted coolie loach (Pangio muraeniformis)
Wolf's catfish (Mystus wolffii) (May be native to river estuaries, but introduced to inland reservoirs)
Dwarf bumblebee catfish (Pseudomystus leiacanthus)
Common walking catfish (Clarias batrachus)
Forest walking catfish (Clarias leiacanthus)
Slender walking catfish (Clarias nieuhofii)
Hasselt's leaf catfish (Silurichthys hasseltii)
Little warty catfish (Parakysis longirostris)
Wrinkle-bellied catfish (Glyptothorax major) (Extinct?)
Javan medaka (Oryzias javanicus)
Malayan pygmy halfbeak (Dermogenys collettei)
Malayan forest halfbeak (Hemirhamphodon pogognathus)
Blue panchax / Whitespot (Aplocheilus panchax)
Oriental swamp eel (Monopterus albus)
Buff-backed spiny eel (Macrognathus maculatus)
Sunda leaf-fish (Nandus nebulosus)
Malayan leaf-fish [(I)Pristolepis fasciata(/I)] (Extinct)
Asian climbing perch (Anabas testudineus)
Forest betta (Betta pugnax)
Tom's giant betta (Betta tomi) (Extinct)
Malayan Pikehead (Luciocephalus pulcher)
Three-spot gourami (Trichopodus trichopterus)
Croaking gourami (Trichopsis vittata)
Dwarf snakehead (Channa gachua)
Forest snakehead (Channa lucius)
Black snakehead (Channa melasoma)
Common snakehead / Aruan (Channa striata)
Marbled goby / Marbled gudgeon / Soon hock (Oxyeleotris marmorata) (May be native to river estuaries, but introduced to inland reservoirs)
Tank goby (Glossogobius giuris)
Bigmouth stream-goby (Pseudogobiopsis oligactis)****
****Listed in older sources as Pond goby (Stigmatogobius poecilosoma)
There are some other species that have been listed in older sources as being present in Singapore, but which might be due to mistaken identity, or errors when recording locations where specimens were collected. The fact that some of these are known from only a small handful of specimens does not help matters, although there is the possibility that they represent species that were dying out in the midst of extensive deforestation during the 19th and 20th centuries.
Other species are listed as originally being native but extirpated, but there is the likelihood that some of these were introduced in the first place, as a number of these are inhabitants of large rivers and lakes, habitats not thought to be prevalent in primordial Singapore.
Next up, the non-native and introduced fishes of Singapore. This is a list that is still growing...