I definitely have experienced dwindle down over the years with Chromis and Bangai. About 4 months ago I picked up 6 Bangai and did a 3 hour acclimmation process with them. And I still have all 6 - Which to keep all 6 is a record for me and Bangai.
But I am also trying to train myself to keep Anthias. So I added a Eheim feeder to the tank and try to feed a mix of pellets and frozen foods a couple of times a day.
So this might explain why I have some short term success with Bangai.
I'm running a fairly high fish load at the moment, and am waiting to come across a nice group of Anthias to try, else I would throw a bunch of chromis in and see how they do.
Outside of the standard Blue Chromis I do have several other types of chromis fish in my tank which have been doing well.