Hi Helene
The unpaired fins have a bright blue edge, then a small black band then a blue band, then solid red. The caudal fin does have a black band but as you say it doesn’t show very well. Ventral fins seem to be blue with pale blue filament.
I will try to get better photos tomorrow, but excited with my new fish so just wanted to try to ID.
Can I rule out bintan do you think?