Oscars are difficult to vent when they're not spawning or getting ready to spawn. So in a sense they can be vented, and they cannot.... I've never had any luck with it even knowing for sure who was male and who was female! I thought, oh great, I have a pair, I know who the female is because I've seen her lay eggs, and I know who the male is so the next time they get moved I'll vent them and take pictures..... They looked exactly the same to me :lol: That and the pictues did not turn out very well :lol:
When spawning or getting ready to spawn a females vent is huge and triangular. The males is pointy ish and not so triangular and not as big as the females.
I hope that helps