I certainly don’t name individual fish within shoals or groups (tetras, Cory’s, guppies, Otos). However, my wife and I have come up with names for individual silver dollars (currently 12 in two tanks, and one new one in qt), because it makes easier to talk about them among us, referring to individual fish, which we do often. And then, 2 Cory’s were born at two different times, first Dory and then Lori. The other fish don’t have names.