I’m not a huge fan of arowana but that top picture has my heart.
Question, is the blue coloring the result of food? Perhaps it’s been groomed to show blue? Genetics?
Genetics. Literally just that. The fish hasn't been "tanned" or "groomed". It's been growing up in a blacked out tank with 0 light on it in the breeding farm in Malaysia. And now in my 10 ft tank without anything of that sort either. As far as seeing the full amount of base color the fish has, there needs to be some decent amount of daylight hitting the tank. My tank is about 10' away from my balcony and around 11AM-1PM I'm getting some decent daylight into the side of the tank.
Pic 1, 2 and 3 are 3 different Arowanas too, so you can see in pic 1 and 2, the fish are both in pretty much the same position and as you can see in both pics, the daylight reflects a bit. The genetics fish 1 has is just better than fish 2. Although, fish 2 does have crazy nice base color too, it's just different (more light base) and fish 2 also crossed (fully) faster than fish 1. So yeah, just genetics... I don't do anything special and in my 10 ft tank, the fish have one white T5 (6500 Kelvin) bulb above the tank. Thats it.
I had to learn this the hard way. Was told the Arowanas I bought in the past are high grade fish, they're gonna turn out really good when you grow them out... did all that and they turned out, to be really harsh, trash... this time I didn't trust an importer again that does this sh*t to make a lot of money. I went directly to the farms, found the right farm and did all the paperwork, Cites preparation etc. myself.
So, to me all this WTT, tanning, grooming stuff is nothing but nonsense. I've tried WTT when my old Aros would turn out to be of bad quality and the importers promised me this WTT nonsense will help - it never did. I have a friend in Germany that has a crazy nice Super Red Aro, currently about 15¨ and already extremely red. Full red cheeks (and real ned, not orange like many). The fish hasn't ever been tanned, never seen a tanning lamp, never seen the sun. How is it that red? Simply put, genetics. And it's still quite a young fish, so it'll get even more red in the next 1-3 years.
