i Can´t give you a 100% answer.
But i also think that that could be a congicus or a endlicheri x congicus.
Endlicheri for sur not !
The colouration don´t look like endlicheri and also the form of his hed exclude a endlicheri,although the picture from above seem´s him to like a endlicheri.
But yeah it´s very difficult to say,what kind of Polypterus he is fore sure.
In the end i would incline to say that´s a endlicheri x congicus,because he has both tees.