Asian Arowana (Scleropages formosus)
Scientific Name: Scleropages formosus
Common Name: Asian Arowana, Dragon Fish
Care Level: easy
Size: 36 inches
pH Range: 6.0-7.0
Temperature Range: 24-30 degrees Celsius (76-86° F)
Origin: Asia
Temperament: moderately peaceful
Compatible Tankmates:
Compatible tankmates include fish of similar size or even larger such as giant gouramis, peacock bass, datnoids and clown knives.
Diet:
Carnivorous.
Tank Size for Adult: 300g.
Narrative:
Asian arowanas are firm favorites in the world of arowanas. They grow to 36 inches in length. Based on wikipedia, Asian arowanas have long bodies; large, elongate pectora fins; dorsal and anal fins located far back on the body; and a much larger caudal fin than that of their South American relative, the silver arowana,
Osteoglossum bicirrhosum. The mouth is oblique with a very wide gape. The prominent lower jaw has two barbels at its tip. The gill rakers are stout. Asian arowanas bear teeth on many bones of the mouth, including the jaws, vomer, palatines, pterygoids, parasphenoid, and tongue.
Their bodies are very laterally compressed with a large upturned mouth, large scales and barbels on their lower lips. To differentiate between the third species of the genus, the Asian arowana (
Scleropages formosus), the number of scales in the lateral line is 32-35 in
S. leichardti and
S. jardinii while
S. formosus has only 21-25. The saratogas are greenish-grey to brown on the back and coppery gold (
S. jardinii) or silvery green (
S. leichardti) on the flanks. One to three red-orange spots can be found on each scale of S. leichardti, while
S. jardini appears to have minimal body spots, the majority of these scale spots appear to have fused creating line markings instead. The fin colours are similar to, or darker than its body colour. Both species have spots present on their fins and tail, with
S. leichardti having numerous small spots-in-lines and
S. jardini having less but larger spots. The spots may be yellow to orange to red for S. jardini, with spots usually red-orange for
S. leichardti. The more northern species (
S. jardini) commonly shows a pattern of squiggly lines and or dots on and bordering its gill plate, this is not present (to my knowledge) in the southern species (
S. leichardti). Another characteristic of
S. jardini is its head which slopes downward from it's back often making it's head look smaller in comparison to it's body. On the other hand
S. leichardti shows no sloping head and is generally more level with it's back.
Asian arowana scales are large, cycloid, and, in some varieties, metallic coloured, with a distinctive mosaic pattern of raised ribs. The lateral scales are arranged in horizontal rows numbered from the most ventral (first level) to the most dorsal (fifth level), with dorsal scales designated the sixth level.
Asian arowanas are distinguished from Australian congenerics
S. jardinii and
S. leichardti by having fewer (21-26) lateral line scales (versus 32-36 for the Australian species), longer pectoral and pelvic fins, and a longer anterior snout.
Green arowanas are dark green on the back, silvery or golden green on its sides, and silvery or whitish on its ventral surface, with dark greenish or bluish patches visible through the lateral scales. In mature fish, the top of the eye and the head behind the eye are bright emerald.
Both grey-tailed and yellow-tailed silver Asian arowanas are dark grey on the back and silver on the sides, with dark ring patches on the lateral scales and a silvery or whitish belly. In yellow-tailed specimens, the fin membranes are yellowish with dark grey rays. In grey-tailed specimens, the fins are uniform dark grey.
Mature red-tailed golden arowanas have brilliant metallic gold lateral scales, gill covers, bellies, and pectoral and pelvic fin membranes, although the back is dark. In juveniles the areas destined to develop golden colour start out metallic silver. The anal fin and the bottom portion of the caudal fin are light brown to dark red.
Mature gold crossback arowanas are distinguished from the red-tailed golden arowanas by having metallic gold crossing the back completely. This variety also lacks the reddish fins of the red-tailed golden.
In mature super red arowanas, the gill covers, lateral scales, and fin membranes of these fishes are metallic red, with the exact hue varying from gold-tinged to deep red. The back is dark brown. In juveniles, the darker the dorsal colouration, the deeper the red will be on maturity.
The Asian arowanas are listed as endangered by the 2006 IUCN Red List, with the most recent evaluation taking place in 1996. International trade in these fishes is controlled under the Convention on the International Trade in Endangered Species of Wild Flora and Fauna (CITES), under which it was placed on Appendix I, the most restrictive category, in 1975.
S. formosus is one of only eight fish species listed on Appendix I. There are a number of registered CITES breeders in Asia and the specimens they produce can be imported into several nations. Other nations restrict or prohibit possession of Asian arowanas; for example, the United States has listed this species under the Endangered Species Act, and therefore it cannot be possessed in that country without a permit.
Declining habitat is a major threat. For example, Asian arowanas are now uncommon in the Malay Peninsula, where they were once widely distributed, due to environmental destruction. Inclusion in the IUCN Red List was originally based not on biological reasons but on practical ones: though widely distributed throughout southeast Asia, they have been harvested heavily by aquarium collectors. However, habitat loss is likely a greater threat than aquarium collecting.
There is no recent evaluation of conservation status by IUCN. Additionally, considering the current confusion as to number of species as well as the wide distribution, conservation status needs to be reconsidered. All strains are probably endangered, but some more critically than others.
The Asian arowana's high value as aquarium fish has impacted its conservation. Its popularity has soared since the late 1970s, and hobbyists may pay thousands of U.S. dollars for one of these animals.
Beginning in 1989, CITES began allowing Asian arowanas to be traded, provided certain criteria were met, most notably that they were bred in captivity on a fish farm for at least two generations. The first of these farms was in Indonesia. Later, the Singapore government's Agri-food and Veterinary Authority (then called the Primary Production Department) and a local fish exporter collaborated in a captive breeding program. Asian arowanas legally certified by CITES for trade became available from this program in 1994.
Captive-bred arowanas that are legal for trade under CITES are documented in two ways. First, fish farms provide each buyer with a certificate of authenticity and a birth certificate. Second, each specimen receives an implanted microchip, called a Passive Integrated Transponder (PIT), which identifies individual animals.
Genetic fingerprinting has been used to assess the genetic diversity of a captive population at a Singapore fish farm in order to improve the management of this species. DNA markers that distinguish among different strains and between sexes have been identified, allowing aquaculturists to identify these characteristics in immature animals.
Reference:
http://www.aquariumhobbyist.com/
http://en.wikipedia.org/
