|Named By:||Louis Agassiz in 1835/39/43|
|Time Period:||Late Devonian-Mississippian~383-318 Ma|
|Location:||Possibly worldwide with some known locations including Belgium, Russia and the United Kingdom|
|Size:||About 50 centimetres long, some variation between species|
|Classification:||| Chordata | Sarcopterygii | Porolepiformes | Holoptychiidae ||
Holoptychius is an extinct genus of porolepiform lobe-finned fish from the Middle Devonian to Carboniferous (Mississippian) periods. It is known from fossils worldwide. The genus was first described by Louis Agassiz in 1839.