Signs of Stress?

[Chad]

Ok, I can never find a definitive guide on this.

What are the signs that a fish is stressed? Not looking for fish specific, but hey if you know fish specific ones please list.

I am pretty clueless except for obvious one such as gasping. But I have heard of clamped fins (which I am still not sure I understand what it means).. is it clamped all the time or just when they swim slowly, etc etc.. Hopefully you get the idea!!