The pics of Edvet don’t show P. sumatranus but a form of the (Sumatranian)-bintan-like variants.
The short (!) filament in the tail of sumatranus must be visible in fish of that size; it’s 1 mm only, but here it’s not to be seen at all.
The rounded spot to be seen in some individuals is not conclusive of sumatranus; it is present in some bintan-variants, too. It is much more distinct and peculiar in sumatranus.