While both are equally rare and highly sought after in the trade, they’re not impossible to obtain and a few specimens have entered the aquarium trade in the past.
Of course, almost all specimens captured have made their way to Japan, as seen by the picture above from BlueHarbor. Both species may look identical at first glance, but they can be differentiated from the anal fin and the tail. B. neopercularis has a thicker red band on the anal fin while B. opercularis has a thinner one.
While the difference between the two is minute, it just goes to show how little it takes to warren the differentiation of two species. We don’t know how different the two species are genetically, but based on appearance, its safe to say that they’re almost carbon copies of each other.