I have some Hornworth in the my water plant pot outside. I tried putting it in the tank and it does well until water changes. It grows like crazy, but after a water change, all the leaves falls out. So I usually end up removing it.
You could try EBJD's for blue or maybe a Gold Saum for blue/green iridescence. I'm not too familiar with the temperament of aro's or argenteas. Maybe a bifa could add some good red to the mix?