As above best with rainbows is multiple females to one male. Usually for a proper school I prefer 2 males and 4+ females. Males will chase females, thats just their nature. its just important to have multiple females so he doesn't chase any particular one too much. I always go with 2 males usually so they have to spend some of their time displaying with eachother about WHO gets to chase the females around. Rainbows have a hierarchy in a group and are really fascinating fish with complex social order when in a proper group. Mine spawn early morning so they are always very active then and that activity calms down during the day.
Its also very common for rainbows to show washed out colors like in your pics when not kept in a proper group/environment. Their mood has a strong influence over their colors and they can change colors/shades pretty rapidly depending on the species.