Not sure if food plays a big role, but I think it does help. I feed my arowanas the same way, market prawns and hikari floating carnivore pellets. market prawns contain carotene which if I’m not wrong helps with the colouration of the fish.Sometimes I feed tiger barb feeder fish, but i usually quarantine the tiger barbs in a separate tank for at least 2-3 weeks.
i just use a normal white light for my tank. I’m terms of Asian arowanas, RTGs, HBRTGs, banjar reds, green arowanas do not require any tanning. Only XB golden arowanas, super red arowanas or blue base arowanas require tanning.
I guess each individual arowana boils down to its genetics mostly in terms of scale shine and colours