Rhizodus (rise-oh-duss) was a genus of lobe-finned fish that lived during the Carboniferous period in what is now Scotland and Ireland.
Growing to 6 and possibly even 7 meters, and possibly weighing up to 4,000 kilograms, Rhizodus is the largest known freshwater fish to have ever lived. It would have appeared elongated and would have possessed large and powerful jaws.
The living creature
Rhizodus was the apex predator of its environment, far larger than any other known animal at the time. It would have fed on amphibians, tetrapods, and other lobe-finned fishes.
Aside from being the largest known freshwater fish, Rhizodus is also stands out as being the only truly massive lobe-finned predator known. Hyneria, which gained fame due to its appearance in the miniseries Walking With Monsters along with the incorrect length estimate of 5 meters, was actually probably between 2 and 4 meters.