Armored Catfish

[greenleaf888]

I have a pair of Megalechis thoracata and they are a joy to keep, they are very peaceful, active and hardy even coming to the surface for food. I have had mine for around half a year now and they have grown substantially, but I suspect they may yet double in size. I was wondering if anyone can tell me how to tell the difference between males and females. I was reading that sexually mature males has thickened first pectoral rays that are scarlet in color.. Both mine seem to have a thick front pectoral ray, but it is brown like the rest of the fish so I am not sure if they are male or female.

If anyone else has kept these guys, I would like to share info on them. Thanks