All of these angels can form a pair by adding a smaller one (juveniles) to the resident angel. If the new angel is a juvenile rather than adult, they will form a pair. I have done this with Regals. Dwarf and Pygmy angels are easy, just add small ones. Lamarck angel is really easy, they are clearly dimorphic, but adding two juveniles or females and you will have a pair.I believe that to be able to form pairs or harem for those angels that do not have sexual dimorphism it is necessary to add all the animals at once, right? a pair of Red Sea Regals would be wonderful, but is it possible to introduce another one after one has already acclimated?