They're just that way sometimes, they'll get better over time. Try to approach the tank slowly and with no sudden movements. But don't approach so slow that they will feel if you are stocking them. Also make sure the room is well lit so they do see you coming, don't want to surprise them. Also keep from wearing the colors of red, orange, and pink these colors do affect some aros. Spend time with them, eventually they will realize that you are not a threat.