The hybrid fishes described herein are _Chrosomus erythrogaster_ (Rafinesque) × _Notropis cornutus frontalis_ (Agassiz), _C. erythrogaster_ × _Semotilus atromaculatus_ (Mitchill), _Campostoma anomalum plumbeum_ (Girard) × _S. atromaculatus_, _Gila nigrescens_ (Girard) × _Rhinichthys cataractae_ (Valenciennes), and _Notropis venustus venustus_ (Girard) × _Notropis whipplei_ (Girard).

Two of the combinations have been reported, without descriptions, in literature (citations below), and Hubbs (1955: Fig. 3) graphically indicated hybridization between the same genera with which this paper is concerned, but did not designate the species involved.