I recenty bought a few anthias for my tank and it is clear they are under some stress. No worries that is expected, but it has caused me to think about stress in fish. One of the signs of sickness is stress, correct? Or at lease stress symptoms...so what are they? What should I keep and eye out for?

Things like:
gaping mouths
"panting" gills

What else? behavior of fish???

Thanks!