The new fish are probably very stressed. And might be overfed even before you buy it. Just keep your tank and filter clean, observe for a while more. Not due to plastic bag. And don't put your face too near the tank, observe from a distance. At times you can wingle your fingers and call for the angel fish to come to you. Angel babies do school but adult may fight. You can goto Vista Point LFS behind the market there to watch this behavior. He have about three schools of babies there. Wingling your fingers will allow them to follow your hand. Running a cloth to wipe the glass will also cause stress. Angels are timid, remember that. Never never tap the glass, scare the hell out of them.