The bartletts are awesome, numbers can matter.
I bought five, lost one immediately, and of the remaining four, one became the shadow male and subsequently had it's eyes taken out by the dominant male.
It lived out it's life in the rockwork, never wanting to give up the quest. I lost all the anthias in a cucumber incident, they were the only ones to go.
I fed them as much as my other fish got. That was twice a day as a rule.