Adontosternarchus is a genus of ghost knifefishes found in Amazon and Orinoco river basins in tropical South America.

They have blunt snouts, a dark-spotted or -mottled pattern on a pale background (however, spotting/mottling can be so dense that individuals appear almost all dark) and reach up to 18.5–32.2 cm (7.3–12.7 in) in total length.

[1][2][3] They feed on zooplankton and can be found quite deep, with A. devenanzii recorded down to 84 m (276 ft).

[1] There are currently six recognized species in this genus:[2][3]

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