I'm fascinated by these claims that this species of giant gourami likes high flowing rivers. I was always led to believe that all gouramis prefer still or extremely slow flowing waters, even their much smaller community tank cousins.
Their shape alone tells you they aren't suited to high flow environments. They are also labyrinth fish. Evolution has given them this ability to breathe air from the surface when the oxygen levels are low. Since when are oxygen levels low in fast flowing rivers!!!
Even my RTGG sulks in a less turbulent area of the tank when my powerhead intermittently comes on. When it goes off he comes back out.
All the clues are there in my eyes.
But I'm happy to be proven wrong, especially if the locals of these catchment areas do indeed regularly catch them in fast flowing turbulent areas.
I think this is similar to cases of other fish filling niches that their group typically does not fill.
septemfasciatus does appear to be the odd one out of the genus as exodon, goramy, and laticlavius all appear to be found in lower flow environments (as with most gouramis). It seems septemfasciatus while caught often in high flow environments is also found residing in river bends/more stagnant areas. They don’t seem like much of a swamp dweller either.
The ability to withstand high flow/consume a more protein dense diet is likely what partitions this fish from O.laticlavius which is found dwelling in the swamps of Borneo.
pictured is an O. septemfasciatus caught somewhere in the rapids of the Kapuas