They can often spend more time alone and when it's feeding time, they don't usually push their way to the top as the males do. There are usually more males than females that survive out of a clutch. This could be because the females are not as assertive, even at a young age, so they don't grow as quickly or as strong as their male counterparts.
The angel above was originally named "Alfred". I noticed this one was hanging back, away from the others, and did not eat with the rest of them. I began feeding this one individually but realized when it became an adult that it is a female. She has been renamed Alfreda. She still spends a great deal of her time alone, staring outside the tank. She is almost two years old. Angels can live to be ten years old.
You can have any number of females in a tank, but when you have only 1 or 2 females and several more males, there can often be a display and posturing between the males as they compete for the female's attention (and eggs).
Females tend to become aggressive only when they are protecting their eggs or their young.