Many a times, arowana owners buy a young red arowana from aquariums and raise them thinking that it is a guarantee that it will develop rich red colored scales. They can wait for a few years and their arowanas just does not seem to become red. The fact is that if you have bought a grade 1.5 or a grade 2 arowana, there is a really good chance that it will not grow up into the nice red color that you want. These are just naming conventions and does not reflect on the eventual color of your arowana.
There are just a ton of naming conventions for red arowanas. You would have probably come across super red arowanas, chili red or blood red arowanas. A lot of farms create names based on their own brands so there is no official or formal naming convention or classification.
There are certain factors that will help to bring out the deep red color in a red arowana. Prolonged exposure to sunlight is one of them. Unfortunately, most hobbyists keep their fish at home and if we exposed the tank to constant and direct sunlight, there would have been an excessive algae growth in the tank.
Another thing that will help increases your chances of getting your arowana’s color out the way you want it to be is to increase the consumption of food high in carotenoid content. You can feed your red arowana prawns frequently because their shells contain carotenoid. Do take note that you are to remove their heads first because it contains sharp parts that may hurt your fish. Another trick is to feed carrots, which are high in carotenoid content, to meal worms and then feed the worms to your fish.
You cannot be guaranteed of a deep red arowana but there are things you can do to increase your chances of getting one.