Tank size: Shoaling fish so group of 5 or 6 needs prob 120G to 150G tank
Temperature: 78F does well for most tropical fish and is what my bala's live at
Plantlife: Anything really, won't harm the plants to my knowledge
Decorations: Anything again but try not to have too many sharp edges.... they are quite skiddish and run into things when they get spooked and could hurt themselves... mine consistenly have scales missing from running into things
How many: Shoaling, atleast 5 or 6 for a happy group....if you have a bigger tank, then the more the merrier
Temperment: very peaceful and can work with almost all community fish... would stay away from more aggressive fish as these guys are lovers, not fighters. Although I am planning on putting them with an Oscar when I get my new tank (the oscar is much slower and should cause no problems to the bala's).
Ideal water stats: normal water stats with temp 78F or so and pH from 7.0 to about 7.5
O and just thought of this... to go with decorations, i would say keep to a minimum.... they are def swimmers and will pace up and down your tank so the more swimmin room you give them, the better (also cuts down on the things they run into when they get spooked.... here is a pic of my tank showing the open space:
wow... just realised that this is an old pic, I've changed it a pic since this was taken, made a few additions too