My female Atabapo I at 6" total length had red in the cheeks. I suspect the lighting and lack of substrate are causing the pike to look faded. Stress will also cause the pike to look faded and lack red coloring.
Looks like a female (black dorsal stripe). Should start getting creamy red body, bright red head and light blues in tail at about 8-10"
Sent from my iPhone using MonsterAquariaNetwork app
Both male and female atabapo I have a black dorsal stripes. This looks to be a male since there doesn't appear to be a white line in below the black dorsal stripe. This white line will show at 6" and get more prominent as the female grows.