Most catfish in asia have some form of teeth or a rough patch in the mouth etc, mekong giants dont its 100% smooth, thats how i tell them apart from the rest in thailand
... oral teeth and gill rakers present in small juveniles, absent at about 30-50 cm SL..."
Summary of differences of MGC or MGC x IDS hybrid --- versus --- IDS on the basis of the GFK's thread above:A very relevant thread by GiantFishKeeper101: https://www.monsterfishkeepers.com/forums/threads/found-mekong-giant-catfish.700708/