Insecure / scared ,
my aro takes refuge in a bottom corner every now and then and swims up when it sees me aproach to feed . Not often but enough to notice . I spend a bit of time by the tank and throwing in small amounts of food to get a long interactive feed . Then he will be fine , I will see if I can catch it on a vid for you . I don't think it's anything to worry about if water parameters are ok and the aro is feeding