Fishes Class Actinopterygii Woodward, 1891 - ray-finned fishes Order Osteoglossiformes Berg, 1940 - bonytongues 1 Family Osteoglossidae - bonytongues and arapaimas 2 Family Pantodontidae 3 Family Hiodontidae Cuvier & Valenciennes, 1846 - mooneyes 4 Family Notopteridae - knifefishes 5 Family Mormyridae - elephantfishes 6 Family Gymnarchidae