I have had had some trouble over the last month with nitrates and illness, but I think that is almost behind me. Now that I am not putting out fires each day, I am realizing that the fish are always on one side of the tank and I am curious as to why. I know the glo-tetras are very fond of the fake bonsai. Now when the two healthy Black Neon tetras and the rasbora are very active they do swim around the whole tank. Otherwise they all tend to be on the left side. I have theories, but don't know. 1 Is it because of all the stress they have endured they want to be together? 2. Is it the heater being on the left? Should I have it centered. 3. Do I have the water flowing, disturbing the water too much on any one area? There is a power head pointing up just to the right of the heater, a penguin 150 right of center and then an air stone in the right rear. They don't seem to have trouble navigating the water as I don't think there is any current. Now that the fish seem stable, I can start trying figure out these other details, working on stocking, etc.