Looks amazing!
I like the pink, just because it's so unusual to see in the Dark side, (maybe together with some dark shading like the red has could look good?). but all the color combinations look solid to me. I would add some nice lighting to the dark ones so that you wouldn't lose all the detail.
Have you looked at some exotic fish for reference? I think you could find some nice color inspirations there too.
PS hell yea capricorn's the best sign