Depends on the bloodline, but usually the red gets more prominent as the fish gets older. So this fish is going to be very dark as an adult - if that is true.
The uniformity of the scales is the most important thing after the usual, conformation, skin quality, correct number of fins.
But a lighter fish is considered more appealling.
Syusuii, like asagi, should look like the setting sun, red on the horizon (bottom of the fish), blue in the sky (top) and elegant.
"To bosom friend, to gracious host
To those who fall, and those who lift
To those who give, yet mark not gift
To healing, hope, and circumstance
To faith, to fate, to meetings chance"
-Bob Kublin (who I have not met)