The juvenile colour within this complex is quite similar.... you need a specimen with a minimum size of about 20cm to say more exactly what it might could be.....
i have 2 blue Channa marulioides with 45cm and 65cm sizes.dorsal fin and pelvic fin dark blue. their backs dark blue, but to methey still Channa marulioides.
I'm not expertise but for your juv pic, at that size it is not Marulia.
It's the same with baby Thai Marulioides that I got.
If it's Indonesia local fish, it should be Marulioides (or Melanoptera... I don't know).