Is the behavior of my tetras, normal?

I read that tetras are "middle swimmers" and that they tend to stay towards the middle section of the aquarium and swim at that depth. I have a 10 gallon tank and 3 neon tetras, but the fish seem to always be in the corners of the tank, hiding. They are usually all together, or two will be in one corner while one is in another. Two of them get fairly excited when I feed them, and the other (Flo) hangs back and waits for the food to settle to the bottom of the tank. They feed souly upon flakes right now, but I'm going to try some freezedried tubifex worms. Any pointers or comments?