Frequently, when reading about Keyhole Cichlids, I come across recommendations to be careful not to startle the fish when doing water changes or other types of tank maintenance. Does anyone know exactly what these authors mean when this recommendation is made? I mean in order to vacuum gravel you have to stick the siphon tub in the tank and disturb gravel (and fish). Is there a careful way to do this? What general precautions can one take to avoid stressing fish while performing maintenance? Sorry if I sound grumpy, I should not really ask questions when I am tired.