RubenD wrote:
Everytime I add a new fish to my tank, the other tenants surround it and
show some territorial behavior, especially my dear damsells. This cause
stress to the new fish. My questions is, if you add the fish with the
lights out, would it make a difference in the morning?



there are two proper ways to add new fish to a tank with Damsels.

Method 1: Don't add new fish, you have Damsels.

Method 2: Take the Damsels out and replace them with the new fish.

There's a reason you can get most Damsels for under $5.