Your experience is very typical. Marine tanks can be very easy to
keep. I have never lost a damsel due to the cycling process, but they
have killed one another. A recent experience with a friends tank has
shown me that your local water source has a lot to do with your
success in keeping a marine tank. I'm not saying that you have an
especially good water source, just that you don't seem to have an
especially bad one.
Unnatural behavior is the easiest way to identify fish stress.
Skittish fish can be stressed or not, depends on the fish. If an
established fish seems over sensitive to what's going on outside the
tank, it is likely stressed. Rapid gill movement is also another sign
of stress. Because your fish are busy doing what they enjoy,
rearranging your tank, they seem happy to me. A stressed damsel can
be very jumpy, cowering, or oblivious to his surroundings. (ie,
swimming head long into a rock or tank wall - at full speed)
--
Dave O'Brien (da...@mipon3.intel.com)