Well there's many ways(venting, kok, fins, ect) But the best and sure way is when her tube drops and you see eggs, and how to tell if the fish is a male, is when he trys to ferutalize the eggs!! LOL!!
hahahah finally a thread just for silks...will post my pics soon of my big boi and his babys =D.and the other batch i picked up recently. any one els breed a thai silk ?