You've done such a marvellous job with the model in the water, if that were cropped it could be a great piece on its own, even reminds me a bit of the art of one of my all times fav artists Victorian Frances, with the gothic outfit, violin and reddish-purple hair.
Your model on the right however just doesn't seem to blend well with the background. You can tell it was originally set in daylight while your background is set in a night time. Even with the glow coming from the water, it still looks a bit off. If you could fix the lights on her arm by painting and added some blue hues to her, I think it would blend better with the rest of the image.
And I am so getting the chills looking at their outfits in a cold winter setting