n = 10
| Scientific Name | Author | Valid Name | Family | English Name |
|---|---|---|---|---|
| Gymnorhamphichthys apurensis | Fernández-Yépez, 1968 | Rhamphichthys apurensis | Rhamphichthyidae | Longnose knifefish |
| Gymnorhamphichthys bogardusae | Lundberg, 2005 | Gymnorhamphichthys bogardusae | Rhamphichthyidae | |
| Gymnorhamphichthys bogardusi | Lundberg, 2005 | Gymnorhamphichthys bogardusae | Rhamphichthyidae | |
| Gymnorhamphichthys britskii | Carvalho, Ramos & Albert, 2011 | Gymnorhamphichthys britskii | Rhamphichthyidae | Drop Knifefish |
| Gymnorhamphichthys caianus | (Triques, 1996) | Iracema caiana | Rhamphichthyidae | Dashed knifefish |
| Gymnorhamphichthys hypostomus | Ellis, 1912 | Gymnorhamphichthys hypostomus | Rhamphichthyidae | Morse Knifefish |
| Gymnorhamphichthys hypostomus petiti | Géry & Vu, 1964 | Gymnorhamphichthys petiti | Rhamphichthyidae | |
| Gymnorhamphichthys petiti | Géry & Vu, 1964 | Gymnorhamphichthys petiti | Rhamphichthyidae | |
| Gymnorhamphichthys rondoni | (Miranda Ribeiro, 1920) | Gymnorhamphichthys rondoni | Rhamphichthyidae | Mousetail knifefish |
| Gymnorhamphichthys rosamariae | Schwassmann, 1989 | Gymnorhamphichthys rosamariae | Rhamphichthyidae | Sand knifefish |