Less-derived teleost fishes are also sometimes considered “primitive”, such as members of Osteoglossiformes (bony-tongues), which include old-world knife fishes (Notopteridae), arowanas (Osteoglossidae), arapaima and African bonytongue (Arapaimidae), African butterflyfish (Pantodontidae), and aba-aba (Gymnarchidae).

Primitive fishes also include cartilaginous fishes (Chondrichthyes; sharks, rays, skates) and jawless fishes (agnathostomes; lampreys and hagfishes).