The subfamilie Osteoglossinae consists of two genera:
Genus Osteoglossum
Genus Scleropages
The two genera have a very disjunct distribution. Osteoglossum lives in tropical South America and Scleropages in S.E. Azia and Australia.
Genus Osteoglossum.
The two species, Osteoglossum bicirrhosum Vandelli, 1829 and Osteoglossum ferreirai Kanazawa, 1966, have two long barbels on the chin, the upper profile of the head running straight into the outline of the back, the lower outline of the head makes an acute angle with the forehead, the mouth extends to a line below the large eye. The unpaired fins are rather long, the dorsal fin is quite low, the anal rather deep. Juvenile specimens of both species are brightly coloured, adults silvery with darker backs. O. bicirrhosum gets about 100 cm in length. It lives in Guayana and the Amazon basin.
Genus Scleropages.
Similar in body shape of the head, but with a shorter, deeper dorsal fin are the three species of Scleropages. They may attain 90 cm in length, the females are mouth brooders. The number of scales in the lateral line is 32-35 in S. leichardti and S. jardini while S. formosus has only 21-25. The saratogas are greenish-grey to brown on the back and coppery-gold (S. jardini) or silvery-green (S. leichardti) on the flanks. S. leichardti has one or two orange-red spots on each scale, while S. jardini appears to lack body spots, having moon shaped edges to its scales instead. The fins 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 depending on the individual fish. The more northern species (S. jardini ) commonly shows a pattern of lines and or dots on and bordering its gill plate, this is absent in the more southern species (S. leichardti ).
- Scleropages formosus 2 (Schlegel and Müller, 1829) lives in Thailand, Mekong basin, Malaysia, Borneo, Sumatra.
- Scleropages jardini (Saville-Kent, 1892) in the northern rivers of Australia, Papua and West-Irian.
- Scleropages leichardti Günther, 1864 is restricted to the Fitzroy river-system, eastern Australia, just below the tropic of Capricorn.