Well is it just kind of "sitting" there or is it frantically trying to swim into the corner?
Sometimes fish will "pace" the tank if they see reflections of themselves in the glass, or if they don't have enough swim space, or are just plain neurotic like that...
Hiding is generally a sign of stress, illness, or being afraid of something (either you or other fish in the tank).
Trying to "swim out of the tank" can sometimes be an indication of poor water quality, stress, etc. Check your water parameters with a liquid test kit (Ammonia, Nitrite, and Nitrates). Ammonia and Nitrite should be zero...above .25 ppm is toxic. Nitrates should be below 20 ppm if possible, and if over 40 ppm start doing a good water change.