Arowanas forms the Osteoglossinae subfamily of bony tongues.
These fish have bony heads, elongated bodies, and large, heavy scales.
However, their most distinctive characteristic is the toothed bone on the mouth floor.
Paleontological records show that some arowana fossils date as far back as the Late Cretaceous, meaning some time between 100.5 and 66 million years ago.
Consequently, only some arowana species have survived in the present times.
Only six species are now inhabiting the world’s freshwater habitats.
Moreover, one species is Endangered, and another is Near Threatened, while there’s little to no information about the Batik arowana.
Besides their “residence” in the wild, some arowanas are also popular pet species.
As such, today we’ll discuss the six extant arowana species, including the Batik arowana.
Until there’s confirmation that it disappeared, we can certainly hope it’s still roaming the world’s freshwater environments.
6. Silver Arowana
The silver arowana is known among scientists as the Osteoglossum bicirrhosum.
It’s native to South America, especially the Oyapock, Essequibo, and Amazon basins.
It inhabits blackwater (slow-moving bodies of water found among forested swamps or wetlands) and whitewater (rivers with high levels of suspended sediment) habitats.
These fish are renowned for their ability to jump out of the water to catch prey – that’s how they got their nickname of “water monkeys.”
They feed on snails, insects, spiders, crustaceans, and smaller fish.
If these fish have a nutritious diet and live in good water and environmental conditions, they can reach a lifespan of 15 years.
Silver arowanas have long, band-like shaped bodies covered in large, silvery scales.
They usually grow up to 3 feet long, but some can reach lengths of up to 3.9 feet.
A silver arowana’s dorsal and anal fins extend to its tailfin, which is much smaller than expected, considering its body length.
There are two distinct barbels on a silver arowana’s head, located on the tip of its mouth.
This is why the species is sometimes called the “Dragon Fish.”
Male and female fish appear similar, although males have longer anal fins and females are more rounded.
5. Black Arowana
Otherwise known as the Osteoglossum ferreirai, the black arowana is native to South America, where it’s found only in the Rio Negro basin.
This fish prefers inhabiting blackwater environments during the dry season, as well as small tributaries and marginal lagoons.
However, black arowanas are primarily found in flooded forests during the high water season.
Like their silver cousins, black arowanas are nicknamed “water monkeys” thanks to their ability to catch prey while jumping out of the water.
These fish eat insects, shrimp, and smaller fish. However, they are also known to feed on small bats and monkeys.
If they live in a healthy habitat that allows them to thrive, black arowanas can reach a lifespan of up to 20 years!
Black arowanas are just as large as silver arowanas, measuring around 3 feet long and rarely reaching 3.9 feet.
Juvenile fish have distinctive black and yellow coloration on their bodies, heads, and tails.
However, as they grow, especially once they reach 0.5 feet long, black arowanas change their colors and exhibit a grayish-bluish coloration.
The number of dorsal and anal fins, lateral-line scales, and vertebrae help to distinguish adults from silver arowanas despite their similar appearance.
4. Asian Arowana
They are part of the Scleropages genus.
They are scientifically called Scleropages formosus and are primarily found in Southeast Asia.
Taxonomic specialists have been debating this species’ classification for years.
Since there are multiple varieties, some consider they should be classified as subspecies, while others believe they are separate species.
These varieties are mainly grouped based on their colors and geographic distribution:
- Green arowanas – found in Vietnam, Indonesia, Myanmar, Thailand, Malaysia, and Cambodia
- Silver Asian arowanas – found on the island of Borneo
- Red-tailed golden arowana – found in Sumatra, Indonesia
- Gold crossback – found in Pahang and Perak, Malaysia
- Red Arowana – found on the Kapuas River, the lakes found in Borneo’s western Indonesian region.
A 2003 study, however, proposed breaking this species into four separate species as follows:
- Scleropages formosus – green arowana and gold crossback
- Scleropages macrocephalus – silver Asian arowana
- Scleropages aureus – red-tailed golden arowana
- Scleropages legendrei – super red arowana
These fish inhabit slow-moving waters found in swamps and wetlands.
They’re primarily active at night when they hunt alone or in small groups. Juvenile fish eat insects, while adult arowanas feed on other fish.
Asian arowanas grow to around 2.9 feet long and have long bodies and large, elongated pectoral fins.
Their caudal fin is much larger than that of silver arowanas, but they also have two barbels on their prominent lower jaw.
As mentioned, arowanas exhibit different colorations.
Besides the scientists’ attention regarding their classification, Asian arowanas are also significant cultural symbols – more precisely, they symbolize luck and prosperity.
Unfortunately, though, the IUCN Red List has assessed the species as Endangered, and their population is constantly decreasing.
3. Jardini Arowana
Otherwise known as the Gulf saratoga, the Pearl arowana, or, scientifically, Scleropages jardinii, the Jardini arowana is native to New Guinea and Australia.
This fish species is found in slow-flowing, clear waters and prefers inhabiting aquatic environments with abundant aquatic plant cover.
Jardini arowanas are opportunistic eaters.
As such, they’ll eat almost anything they can catch, both aquatic and terrestrial prey.
However, they prefer feeding on smaller fish and crustaceans.
These fish have long bodies covered in large scales.
They have a dark brown coloration featuring greenish shades and distinctive reddish marks on each scale.
The dorsal, anal, and caudal fins are brownish-gray and covered in small red spots.
Their average length is 1.8 feet, although some can reach 3.2 feet.
Even though Jardini arowanas have successfully been bred in captivity, they are considered a territorial and aggressive species and don’t do well in community aquaria.
2. Southern Saratoga
You might know the southern saratoga under a different name, as it has plenty – the spotted bonytongue, the spotted saratoga, the Australian arowana, and barramundi.
Scientifically, however, this fish is known as Scleropages leichardti.
This species is native to Australia, precisely to the Fitzroy River system, although it has also been introduced to other waters.
It prefers inhabiting still or slow-moving waters.
Compared to its cousin, the Jardini arowana, southern saratoga’s population number is smaller, and its distribution is more restricted.
In fact, southern saratogas have been assessed as Near Threatened by the IUCN Red List.
On the other hand, there’s no up-to-date information regarding its population numbers because the species is highly territorial and cannot be found in abundance.
Southern saratogas can reach lengths of up to 2.9 feet.
Their backs are dark brown to olive green, while their bellies and sides are of lighter shades.
Southern saratogas can be distinguished by the small orange-reddish dots on their large scales.
Like other arowanas, this species has two barbels on its lower jaw.
1. Batik Arowana
The Batik arowana is also known as the Myanmar arowana since it originates from Myanmar – more precisely, the Tanintharyi River Basin.
It can be distinguished from other arowanas by its unique wavy scale pattern and Batik-like head pattern.
This species has been assessed as data deficient by the IUCN Red List, although there are known records of Batik arowanas from farming and aquarium trade.
On the other hand, since there’s no precise information regarding the species’ exact location in the wild, scientists believe its population is probably declining.
However, until further research and confirmation that the Batik arowana is extinct, we can assume and hope they’re still inhabiting the waters of the Tanintharyi River basin.
Sources
- https://en.wikipedia.org/wiki/Arowana
- https://en.wikipedia.org/wiki/Silver_arowana
- https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=799
- Gomon, M.F. & Bray, D.J. 2016, Scleropages leichardti in Fishes of Australia, accessed 29 Mar 2023, https://fishesofaustralia.net.au/home/species/3293
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