Datnoids are popular in some Asian countries because they are thought to bring good fortune. It's thought to be good luck to have a dragon (arowana) above and tigers (datnoids) below. However, I've always liked datnoids for reasons other than superstition, such as their striking appearance and engaging "personality."
There are five recognized datnoids species:
Datnioides pulcher, widebar datnoid
Datnioides microlepis, Indonesian datnoid
Datnioides undecimradiatus, thinbar datnoid
Datnioides campbelli, New Guinea datnoid
Datnioides quadrifasciatus, silver datnoid
As far as bars are concerned, they are generally only an issue with widebar datnoids, Datnioides pulcher. Wider, darker, and cleaner bars are typically preferred over thinner, more muted, and ragged bars. A full necklace, i.e., a first bar that completely encircles the fish, is also considered desirable.