I keep large groups, 100+ at times of angels together, some smaller groups of adults as well. Once in a while I keep a smaller group of juviniles together.
Smaller groups of angels are more skittish during maintainance than larger groups. They are more comfortable in larger groups. Older fish are more cautious than younger fish. A large group of mixed age fish, adults & juvies, acts the same as a large group of juvies. A large group of adults is more cautious.
They all eat like pigs, with the exception of pairs that have a tank to themselves. Once they settle in to their tank, pairs seem to take their time a little more, I think they realize there is no competition for food.
The younger they are, the less they care about tank maintainance. As they mature, they will go towards the end of the tank where you aren't. Small groups of half a dozen or less adults will hide the second you start messing with the inside of their tank. Once you have around 15 together they feel more secure when you start fooling with their territory. They will hang out around gravel vacs & syphon hoses.
It seems they don't realize where food comes from until they get to around pea body size. After that, they know where it comes from, act hungry always, & will follow anyone from one end of the tank to the other. They also figure out real quick that the dog doesn't feed them, and totally ignore him as he walks by the lower tanks.
Tolak