I have two corys but both are female (i'm not quite sure, both fish are maximum wide between their pectoral fins and the tail, i had 1 male but he died last week), i also have two angelfish 1 male and 1 female.
Is it possible the eggs were laid just prior to the "male's" death?
Corys do lay eggs on surfaces, as others have noted; leaves are often selected, the underside mainly. Chunks of wood, dry leaves, glass tank walls, filter tubes...almost any surface may be chosen. I have about 40 corys of varying species in one tank, and several have spawned on and off. While I have never seen the eggs, I have found fry that survived, three times. Once a fry was swimming in the canister filter and I found it when cleaning the filter.
By the way, I would get at least three more corys. All corys are best in a group, and five is minimum; more will be better, but try not to have less than five. Different species doesn't seem to matter much for most species, in my experience. Among my 40-odd I have some species with 4-5, some with 2, and a couple with just one. They all chum around together. I try to acquire 5-6 of a species, but for various reasons this is not always possible.
Byron.