Love the estitic of this image! The design of the charecter is so different and it's such a nice mix of octopus and human. It's such a fresh design also in comparison to the more "traditional" mermaids floating around the site at the moment. I particularly like the onconventional designelements that you've included such as the eyes and the octupus beak instead of teeth. Very nice. I also like the color contrast and palette with the greens and purples that interplay so great here. The pose and composition also makes it like she's floating. Finally, her expression is a nice mix of fear and confusion. Very intense.
If I were to give some critique I'd like to mention the pattern in the tentacles which I think break the flow of them a bit. On the other hand it adds to your unique estetic, but I'd love to have seen it band a bit to follow the shape of the tenacles. Next, the shading of the tentacles is a bit light in places, for instance the tentacle lowest on her right, the shadow towards the body is lighter than on the tentacle above, which seems counter-intuitive. (Motivation for 4.5/5)
Otherwise I congratulate you on an interesting and uniquely designed piece.