hmm...i just think they look, im not too concerned with them hiding, thats what most of the fish in this tank do lol. Have you had them with other fish by any chance? Do they bother other fish?
Never kept African Butterflies personally, but I have read that they also enjoy floating plants like pike killies. They are known to be jumpers though, make sure all parts of the tank are fully covered.
Rainbows could work in the mid-swimming fish, and look pretty nice. Plus many species grow large enough to avoid predation of your killies when they are fully grown.
Roseline sharks (Puntius denisonii) grow to around 4.5", but in my opinion they look best in large groups (4-5+), but three could do also. They like high oxygen levels. Also commonly called the Denison Barb, though unlike most barbs, it is very peaceful.
Dont think rose lines are what im lookin for in this tank. I looked at em online and they dont care much for the way they look and really dont like the $20 price tag for a fish thats really just going to be a "filler" lol. But im still open to suggestions if anyone wants to throw any ideas out.