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OSTEOGLOSSIDAE



The Osetoglossidae or Bony-Tongued Fish family consists of two sub-families, Heterotidinae and Osteoglossinae; some four genera; and seven or eight species. Bony-tongued Fish inhabit tropical areas of South America, Africa, Asia, and Australia. These prehistoric-looking fish are covered with a layer of large, thick scales. The head is protected with bony plates, and the eye are large. The mouth is hinge-like and faces toward the surface.
The species of this family have been used to support the continental drift theory since members from different areas closely resemble one another. It is believed that members of thus family once existed in North America, Europe, and India, but died off for some reason.
There has been little success with breeding Bony-tongues in captivity due to their shear size. Spawning has been observed in the wild. Some species are mouthbrooders while the rest construct nest from plants and debris.


HETEROTIDINAE SUB-FAMILY
The sub-family Heterotidinae consists of the genera Arapaima and Heterotis, and inhabits tropical South America and Africa, respectively.

Pirarucu, Arapaima, Piache [Pictures]
Arapaima gigas
SYN: Sudis gigas, S. piracuru, Vastres agassizii, V. curvieri
PD: The body is covered with large, thick scales. The tail is small and round and the body is elongated. It has a large, wide mouth that faces upward. Its head to midsection is dark brown to black with blue highlights. From the midsection to the tip of the tail, the scale are dark, but edged with red. The red color becomes more dominant towards the tail.
SIZE: To 16' (4.9 m) in nature, although usually not more than 5' (1.5 m) in captivity.
SS: None
HAB: Inhabits floodplain pools with little oxygen in South America; Amazon and Orinoco rivers.
S: top
TANK: A tank measuring 96" (244 cm) with a capacity exceeding 200 gallons (758 L) is suitable for fish measuring up to 30" (76 cm). Larger fish should be transferred to a larger tank or to a public aquarium. Large open swimming areas should be provided along with areas of plating with large plants. A tight fitting cover is required as this large species can jump. A powerful filtration system to remove waste is needed, although it should create little current. A cover of floating plants to diffuse the lighting is suggested.
WATER: pH 5.8-7.2 (6.7), 2-12 dH (8), 75-86F (24-30C)
SB: Only combine with other large fish of lower swimming levels. A highly predatory fish that acts aggressively towards similar species.
SC: Astronotus, Anostomus, Cichlasomines, Loricarids, Colossoma, Leporinus, Mylossoma, Pseudoplatystoma, Serrasalmus, Sorubim
FOOD: Live; primarily fish, also large crustaceans, frogs; chopped meat; possibly pellets once acclimated.
SEX: Males are redder during the spawning season.
B: Breeding is nearly impossible in an aquarium. Goulding documented the Arapaima's reproductive behavior in nature, at the start of the flood season, the Arapaima prepares a nest in shallow areas of stagnant water pools. Both the male and the female use their snout, mouth, and fins to dig a pit in the river bed. This pit can measure up to 20" (50 cm) in diameter and 8" (20 cm) deep. The female deposits up to 50,000 eggs in this nest, after which the male fertilizes them. The parents drive off predators by loud tail-slaps that they produce when they surface to breathe. The male protects the eggs while the female guards the general territory. The eggs hatch after 4-5 days, and the 1/2" (13 mm) larvae are free-swimming 6-7 days after. The young have functioning gills, but still surface every 4-6 minutes (Goulding 133). The young match the dark color of the male's head, and camouflage well while swimming near him. Once the young are old enough to fend for themselves, after about three months, they are abandoned. Few eggs and fry survive because of heavy predation.
BP: 10. Breeding is not possible in the home aquarium.
R: The Arapaima is the largest predatory fish of the Amazon. It is an excellent jumper and can weigh up to 500 pounds (228 kg). During the dry season, the Arapaima seeks out floodplain lakes with little oxygen they can prey on the abundant fish trapped in a small area. The Arapaima breathes through its swim bladder, which is lined with blood vessels. Adults surface every 10-15 minutes, but can remain without atmospheric oxygen for up to 30 minutes if pursued (Goulding 133). When surfacing, this fish makes a characteristic grunt-coughing sound. The Arapaima does not bite with its mouth or jaw, but uses its tooth-covered tongue to crush prey up against the roof of its mouth. Dried Arapaima tongues were once used as seed graters for soda drink powder (Goulding 134). The Arapaima becomes sexually mature at 5.5' (168 cm). This species is considered endangered in Brazil, and cannot be legally exported form that country. Conservation efforts
DC: 10. This hardy species grows too large to be kept in a home aquarium. This species is best left in the wild where it belongs.

African Arowana, African Bony-tounge [Pictures]
Heterotis niloticus
SYN: Clupisudis niloticus, Sudis niloticus
PD: An elongated, laterally compressed species with a somewhat level back profile. The anal and dorsal fins run along the last one-third of the body. There is a cleft between these fins and the caudal fin. The scales are large and the head is covered with bony plates. The general coloration is a light olive to silver gray, often with a silver iridescence. The head is small, while the eye is large.
SIZE: To 36" (90 cm)
SS: None
HAB: Western and central Africa.
S: top
TANK: A tank measuring 48" (122 cm) with a capacity from 50-70 gallons (190-266 L) is only sufficient for smaller individuals, under 16" (41 cm) in length. Larger specimen require a tank measuring at least 60" (152 cm) with a capacity exceeding 90 gallons (342 L). The tank should be well-covered. Use a layer of floating plants to diffuse the lighting. Leave large open swimming areas and use large plants in the background. The tank should be arranged in dark colors.
WATER: pH 6.7-7.5 (7.0), 4-12 dH (9), 75-86F (24-30C)
SB: This species is combative towards its own species and should be kept singly. Otherwise this species is relatively unaggressive towards fish that it can not swallow. Small fish may be consumed by this predatory species.
SC: Larger Mormyrids, Haplochromis and related cichlids, Xenomystus, Synodontis, Hemichromis, Cichlasoma, Astronotus, Anostomus, Leporinus, Pacus, Silver Dollars, Pimelodids, Loricarids, Knifefish.
FOOD: A plankton and filter feeder by nature that usually accepts live worms, fish, insects, and shrimps in captivity. Acclimated specimen may accept pellets.
SEX: Difficult to distinguish.
B: Breeding has been unsuccessful in captivity because of this fish's size. Spawning has been observed in nature. A large, circular nest is built from plants and mud in a shallow pool. It is built at the beginning of the spawning season by both parents, and its construction takes four to eight days. The sides of the nest reach up to 10" (25 cm) out of the water. The female enters and lays her amber-colored eggs along the inner walls of the nest. She exits and then the male jumps over the embankment, where he fertilizes the eggs. The female participates in brood care, guarding both the eggs and the fry. The fry are said to feed upon plankton.
BP: 10. Not possible in aquaria.
R: These fish are only suitable as a juvenile for most private aquariums. This species is easily spooked, and may panic and throw itself against the tank glass. H. niloticus is a filter feeder which obtains nutrients in nature by filtering plankton and other micro-organisms through its gills.
DC: 7. Besides reaching a large size, some report that the African Arowana is troublesome to feed. This species is generally hardy once acclimated.


OSTEOGLOSSINAE SUB-FAMILY
The members of the sub-family Osteoglossinae are spread across the globe in South America, Australia, and Southeast Asia. This sub-family includes the genera Osteoglossum and Scleropages.

Arowana, Arawana
[Pictures]
Osteoglossum bicirrhosum
SYN: Isochnosoma bicirrhosum, Osteoglossum vandelli
PD: An elongated, slender fish with lateral compression. The scales are large and the head is covered with bony plates. The long anal and dorsal fins extend from the midsection of the body and run to the tail. The pelvic fin is a long, slender, sharp ray, while the pectoral fin is also very slender. These fins are white to silver in color, but may darken with age. The mouth is hinge-like and can be opened widely. Two barbels, which range in color from black to blue to green to red, are located on the lower jaw. The body color ranges depending on the sex, age, and habitat of the individual. Usually the Arowana is white with a silvery iridescence, but is often pink with a rainbow iridescence. The pinkish fish are often referred to as the "Rainbow" or "Salmon" Arowana. The Arowana has two large black spots that fade with age. The first is located in front of the gill cover and can only be seen on young individuals. The second is located behind the gill cover and is dark black with a copper colored mark located next to it. The eyes are large and dark.
SIZE: Specimen measuring 60" (152 cm) have been caught by fishermen in the Amazon Basin, although the Arowana rarely exceeds 44" (110 cm) in captivity.
SS: Black Arowana ( Osteoglossum ferreirai), Asian Arowana ( Scleropages formosus ), Silver Barramundi ( Scleropages jardini)
HAB: South America; the flood plains of the Amazon River and its tributaries.
S: Top
TANK: Young fish (under 6") should not be kept in tank measuring less than 36" (91 cm) or 35 gallons (132 L). Fish measuring up to 15" (38 cm) can tolerate a 48" (122 cm) or 55-70 gallon (209-266 L) tank. Eventually a considerably larger tank will be needed. The tank should be well-covered for Arawanas are fine jumpers. Use a dimly lit tank that is arranged in dark colors and has a cover of floating plants. The tank can be well planted with sturdy plants. An efficient filter is required that can remove large amounts of waste, but not create too much surface disturbance.
WATER: pH 6-7 (6.7), 2-15 dH (8), 75-86F (24-30C)
SB: The Arowana is a large predator that will consume smaller tank mates. This species is aggressive towards similar species and should be singly instead of in pairs or groups. Only combine the Arowana with large, robust species of lower swimming levels.
SC: Astronotus, Anostomus , Cichlasomines, Loricarids, Colossoma, Leporinus, Mylossoma, Pseudoplatystoma, Serrasalmus, Sorubim
FOOD: Live; fish, spiders, large flying insects, Tubifex; may accept pellets and flakes
SEX: Males have a longer anal fin while females are usually fatter when mature.
B: Breeding has only been accomplished a few times in an aquarium because fish become too large. On most occasions, spawning has occurred in a tank exceeding 1000 gallons (3780 L). The eggs are 0.5" (1.3 cm) in diameter. The male mouthbroods the eggs for seven to nine weeks. The fry, measuring 3 or 4" (8-10 cm), leave his mouth after their egg sacs are gone.

Goulding documented spawning in nature. As flood waters rise, the cheek spot of male Arowanas, turns bright pink. Females are attracted to males with bright pink cheek spots, as this indicates that sperm is ripe. The female produces 150 to 200 eggs, which after fertilization, are taken into the protection of his mouth. The young hatch and remain in the mouth of the father. The yolk-sac is used up in 2 or 3 weeks, after which, the male lets them out to feed on microorganisms such as algae, tiny crustaceans, and insects. When danger approaches, the male's chin barbells are used to coax the young back into the safety of his mouth. After 4 to 6 weeks, the young are abandoned to fend for themselves.
BP: 10. Not feasible in captivity.
R: These fish are only suitable as a juvenile for most private aquariums. After they outgrow their tank, it is often hard to sell them and it may be best to donate them to the local public aquarium. They grow very fast, often more than 12" (30 cm) in their first year. Avoid purchasing a fish with an egg sac for the fish is very delicate at that time. When frightened, these fish are likely to swim frantically around the tank, throwing themselves against the tank cover and the tank sides. Often, self inflicted injuries result. The Arowana is an excellent jumper, capable of leaping six vertical feet from the water. During the flood season, the Arowana has been known to use this ability to snatch young monkeys and sloths that are drinking. Unfortunately, most wild-caught juveniles are caught in a very brutal manner. Fishermen can recognize male Arowana with young in their mouth by their colored cheek patches and swollen lower jaw bones. When such a male is spotted, fishermen use an ax in an attempt to sever its head. Severing the head, prevents the male from killing the young by swallowing them, which is usually the reaction when the male is captured with a net. As the young flee the decapitated head, they are captured.
DC: 8. The Arowana is a hardy, predatory fish that requires a diet consisting of live foods. The Arowana quickly outgrows its tank and subsequently must be moved. Perhaps this species is best left in its natural habitat and not cramped in a person's aquarium.

Black Arowana [Pictures]
Osteoglossum ferreirai
SYN: None
PD: Very similar to 0. bicirrhosum except for coloration. Young fish have a brownish gray to dark brown back and black-brown flanks. A wide stripe runs from the gill cover to the tip of the caudal fin. The head is silver-brown and a black-brown stripe runs from the snout, through the eye and to the first gill opening. The gill area is marked with a black-brown vertical stripe followed by a similar white one. The pelvic fins are silver while the others fins are brown-black. The anal and dorsal fins are edged with white to orange.
SIZE: To 40" (102 cm) in nature, although not usually larger than 31" (80 cm) in captivity.
SS: 0. bicirrhosum
HAB: South America; in the Rio Branca, a tributary of the Rio Negro
S: top
TANK: Young fish (under 6") should not be kept in tank measuring less than 36" (91 cm) or 35 gallons (132 L). Fish measuring up to 12" (30 cm) can tolerate a 48" (122 cm) or 55-70 gallon (209-266 L) tank. Eventually a considerably larger tank will be needed. Follow set-up suggestions for 0. bicirrhosum except peat filtration is preferred.
WATER: 5-7 pH (6.4); 1-10 dH (4); 75-86F (24-30C)
SB: As for 0. bicirrhosum.
SC: Astronotus, Anostomus , Cichlasomines, Loricarids, Colossoma, Leporinus, Mylossoma, Pseudoplatystoma, Serrasalmus, Sorubim
FOOD: Live; fish, spiders, large flying insects, Tubifex; may accept pellets and flakes
SEX: Perhaps similar to 0. bicirrhosum.
B: Similar to 0. bicirrhosum; Breeding is only successful in large tanks with soft, peat-filtered water. The fry are sensitive to water quality and the water values should be checked regularly.
BP: 10. Breeding is not possible in most tanks.
R: The black Arowana is a skittish, delicate fish that is best kept in a species tank while young. However, once reaching 12" (30 cm), it becomes a much hardier fish. Only the young individuals have the beautiful color pattern which gave them their name, the adults resemble the Silver Arowana in coloration. Sadly young fish are caught in a similar manner to that of 0. bicirrhosum. Please see "R:" under 0. bicirrhosum.
DC: 8. This large, predatory fish requires a diet of live foods. The Black Arowana must be kept in a large tank. A species that is sensitive while young.

Asian Arowana, Green Arowana [Pictures]
Scleropages formosus
SYN: Osteoglossum formosum
PD: The body form is similar to that of Osteoglossum except that Scleropages has a stockier body, larger scales, shorter barbels, and shorter anal and dorsal fins. The caudal peduncle is very thin when compared with the rest of the body. The caudal fin is fan-shaped. The back is olive while the flanks are greenish gray to olive-silver. A greenish iridescence may be present. The fins are greenish brown. The iris of the eye is red.
SIZE: To 36" (90 cm)
SS: Silver Arowana ( Osteoglossum bicirrhosum), Silver Barramundi ( Scleropages jardini )
S: top
HAB: This species inhabits still streams and creeks in Southeast Asia and Australia; Borneo, Malaysia, Sumatra, Thailand.
TANK: A tank measuring 48" (122 cm) or 55 gallons (209 L) is minimum for young individuals. They will quickly out-grow an aquarium of this size! Use peat filtration. Follow suggestions for O. bicirrhosum.
WATER: pH 6.5-7.5 (7.0); 1-10 dH (5); 77-86F (25-30C)
SB: This predatory species is pugnacious towards others of its own species, although relatively indifferent toward other large fish. Small fish will likely be consumed.
SC: Large Tinfoil Barbs, Clown Knife, Giant Gourami, Cichlids, Asian and South American Catfish (Pimelodids, Loricarids, Auchenipterids, Doradids, Bagrids [ Leiocassis, Mystus])
FOOD: Live; fish, spiders, large flying insects, Tubifex; may accept pellets and flakes
SEX: It is believed that females are plumper when mature.
B: Similar to S. jardini, except 30-50 eggs are produced..
BP: 10. This species has said to have bred in captivity although details are not available at this time.
R: See comments under O. bicirrhosum. The Asian Arowana is protected as an endangered species by the Indonesian government and wild specimen cannot be legally imported. There are several forms including super-red, golden, green, and silver. There is even a rare albino form.
DC: 7. This large, predatory species requires living foods and an enormous tank.


Silver Barramundi, Northern Barramundi, Australian Arowana [Pictures]
Scleropages jardini
SYN: None
PD: The Silver Barramundi is similar in body shape S. leicharati. The back is brown- silver, while the flanks are silver. The frontal region of each scale is gray, while the rear part is silver to orange. This species develops an orange cast with age. The fins are dark gray with various orange spots.
SIZE: To 32" (81 cm) in nature, although usually not larger than 24" (61 cm) in captivity.
SS: Scleropages formosus, S. leicharati
HAB: Australia, Papua New Guinea
S: top
TANK: A tank measuring 48" (122 cm) or 55 gallons (209 L) is minimum for young individuals. They will quickly out-grow an aquarium of this size! Follow suggestions for O. bicirrhosum.
WATER: pH 6.8-7.8 (7.5), 8-16 dH (12), 75-86F (24-30C)
SB: This large, predatory species is aggressive towards its own and similar species. Combine only with other robust, large species.
SC: Larger rainbowfish, large Tinfoil Barbs, Clown Knife, Giant Gourami, Cichlids, Arius catfish, Bagrid catfish, Pimelodid catfish.
FOOD: Live; fish, spiders, large flying insects, Tubifex; may accept pellets and flakes
SEX: The males have a longer anal fin and are distinguishable by their prognathous jaws. The females are usually fatter when mature.
B: This species has been bred on a few isolated occasions in captivity. The female lays 50-200 eggs which are 0.4-0.5" (1-1.3 cm) in diameter. These hatch in 18-30 days and are incubated in the mouth of the male. The young begin feeding on small crustaceans and microorganisms.
BP: 10. S. jardini has been bred with irregularity in captivity. Breeding is not possible in most tanks due to the size requirement of this species.
R: The validity of this species in in doubt. There is debate to whether S. jardini and S. leicharati should be considered separate species or just different morphs of the same species.
DC: 8. This large species requires live foods and a well-maintained tank.

Spotted Barramundi [Pictures]
Scleropages leicharati
SYN: None
PD: Virtually identical in body shape to S. jardini. The back is gray while the flanks are silver with a silver iridescence. Each scale is marked with one or two orange spots. The fins are marked with orange spots. The anal, dorsal, and caudal fins are edged in black.
SIZE: To 32" (80 cm) in nature; rarely larger than 20" (51 cm) in aquaria
SS: Scleropages formosus, S. jardini
HAB: Fitzroy River in Northern Australia
S: top
TANK: A tank measuring 48" (122 cm) or 55 gallons (209 L) is minimum for young individuals. They will quickly out-grow an aquarium of this size! Follow suggestions for O. bicirrhosum.
WATER: pH 7-8 (7.5), 6-16 dH (12), 77-86F (25-30C)
SB: This large, predatory species is aggressive towards its own and similar species. Combine only with other robust, large species.
SC: As for S. jardini.
FOOD: Live; fish, spiders, large flying insects, Tubifex; may accept pellets and flakes
SEX: The females are usually fatter during the spawning season when mature.
B: Spawning has been observed in nature. The male mouthbroods the eggs until fry are able to swim.
BP: 10. Breeding has not been successful in captivity.
R: The Spotted Barramundi is very sensitive to water conditions, more so than S. jardini. The Spotted Barramundi is considered an Endangered Species and cannot be imported.
DC: 9. The Spotted Barramundi grows very large. This predator is sensitive to water pollutants and requires frequent partial water changes. This fish must be fed live foods.

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