6 inches is too small for tanning. 9-10inches is when you start, then you can do soft tanning. Right now you can increase the gold color with a white background for the shine. Use white light 6500k once it’s 9-10 inches putting a white background is critical to increase the gold coverage and when it reaches 14 inches you can change the wallpaper to black or blue and it will work on the base color which is blue to get deeper. Don’t go for any hard tanning lights you will end up burning the scales( hard tanning is only done for super reds).
Diet and water parameters is the most important and if you want to get the best color out of any Asian arowana get a RO system. Low TDS of 50 -100 with a PH of 6.5. Please remember if you get an RO system all your nutrients, minerals and PH will take a hit. So research before you go RO
I would suggest a varied diet from SW, Market shrimps with good pellets inserted in them( if your arowana is not pellet trained) crickets, dubias are best to bring the color out.
Water temp- 26-28 is good I like 27 it’s the sweet spot(degrees Celsius)
Hope this helps, keep the water pristine and your fish will give you the best!!!!
