cardinal tetra breeding

So I have some tetras that’s I haven’t had for long and one is looking pretty fat... lol from what I see online it’s hard to tell the male and female apart so I don’t know if it’s a female. And if it is a female I also read it was hard for tetras to spawn in a normal tank?

Hello My brother has had cardinals breeding in his 60l community tank. It has ember tetras, Siamese fighters, dwarf gouramis, pygmy cories, two baby discus fish and of course some cardinals. He already has had the pygmy cories breed successfully. This morning he found 8mm cardinal fry...