The tinctorius in particular are very territorial. I wouldn't mix them with other species.

Mixing species is rather controversial, although it is sometimes done successfully with carefully chosen species in very large tanks. I wouldn't recommend attempting it, at least until you have first hand experience with each raised separately. In a 40 gallon, you could put 4 to 5 D. leucomelas, because these do get along well in groups, or a single pair of tinctorius, which get along best in mated pairs.

Another choice might be to divide the tank with a vertical piece of glass or screen so the two different species are physically separated.
-----
Patty
Pahsimeroi, Idaho

D. auratus blue, auratus Ancon Hill, galactonotus orange, galactonotus yellow, fantasticus, reticulatus, imitator, castaneoticus, azureus, pumilio Bastimentos. P. lugubris, vittatus, terribilis mint green, terribilis orange.