Pisces

What I like most about this piece is the feeling of peace, stillness, and rest conveyed in the woman's pose, her clothes, her expression and the up swept abundance of her hair. As well as the cool and calming colours, of course, but mostly the woman and her simple beauty.

I like the blue colours you use; generally, I love anything to do with water or the sea. This, contrasting with the glowing warm spots of coral on the dress and brown hair nicely balances the piece.

So, the woman herself. I like her hair the best. It's really perfect: the warm, almost auburn colour, the graceful lines followed by each strand, the heavy shading in parts, and the way it seems to float suspended in the water, just so, leaving the back of her neck clear and exposed. I love how that must feel, with all your hair up and out of the way, no longer a burden.
Consequently, the top of her back is also bare, the only adornment being the two long ties curling delicately and working to balance the displaced mass of hair.
Her hair also balances the dark bottom right corner, being the only other area with shadow of comparable darkness.

I really like the dress: the design and the spots of coral pink that look like the markings of some exotic fish. From the dense concentration at the top, the dots lessen near the bottom, and the fabric becomes mist-like, or cloud-like, seeming to emulate some strange jellyfish. I like the effect here, but it feels a little incomplete and not quite consistent with the very 'controlled' look of her hair. The tendrils of her dress are wild and haphazard, and they don't feel intrinsically 'part' of the rest of dress - they are thin and transparent whereas the bottom edge of the dress is still very dense. I think you should work a little on making the two parts more 'together' (though I really love how the lines glow).
In saying that, the tendrils really add to the piece, continuing that implied line from her hair, curving all the way round to the left side. They also complement her hair, as they too, wind away past the edge of the picture, disappearing from sight.

The background. As I said, the colours are great. The points of bright aqua pulsing amid the deep turquoise hues add a glow to the piece and creates the impression of sunlight filtering through fathoms of murky sea. It also adds to that feeling of stillness and isolation. You've portrayed the ocean so well it's easy to imagine the coldness of the water on bare skin and the endless underwater acres fading in the distance.

What I'm not so sure about is the underwater plants, especially those on the left. They look incongruously 'rough' (compared to the smoothness of the hair and dress) and clash with the glowing strands of the dress. They seem to be far away, but at the same time they're in front of the dress. I think they add clutter to the piece and I would suggest you either get rid of them entirely, or rework them to better fit with the rest of the picture - especially their interaction with the bottom tendrils of the dress. The plants on the right work quite better, I think - they blend with the background and follow a similar curve to that of the woman's pose.

Lastly, the fish. They look pretty and add a bit of colour to the top right, corner but they too feel slightly distracting and incongruous. The main focus should be on the woman, and I feel she needs a certain circle of empty space about her face devoid of anything. The fish do link back to the title 'Pisces' but I feel the idea comes across perfectly with the woman alone.

Overall, a splendid piece. It really catches the eye and holds attention well. Like I said before, the emotion it evokes it lovely and makes me feel just wonderful.