Just got some orange chromides on Thursday. They seem to be feeding well, very eager to eat anything and they already know my feeding signal (I tap on the lid). They keep mainly to the bottom but are still very skittish when approaching the tank. When I feed them they hide behind a plant and dash out as soon as the food hits the water. My question is, is this skittish behavior normal for them or maybe they just need denser planting to feel more secure? thanks!