Black Cap Basslet with Royal Gramma

[AHHope]

I've currently got 3 royal grammas in my 90 gallon. I introduced them all at the same time and have had no problems so there shouldn't be a problem with a gramma and a black cap. Most people don't realize that in the wild both species live in fairly large groups in overhangs in the reef. Only real difference is the depth there found at.