Angel fish breeding

This evening when I cam home from work, I found that my pair of Angelfish
had laid a clutch of eggs on one of the leaves of my sword plant.  One of
them had some kind of appendage sticking out of it was was going over the
eggs with the appendage (I assume it was the male trying to fertilise the
eggs. Am I right?).  Anyway, the lights went out as usual later in the
night and half an hour later when I happened to peek into the tank again,
all the eggs were gone!!

Can someone please tell me what happened?  Did the lights going out scare
the angelfish that they began to eat the eggs?  How long before they'll
start again and what should I do next time?