What first drew me to dwell on your photograph were the colours and the way the water looks from below the surface. Secondly, the turtle's gaze is upon you and inspires me to wonder what it's thinking as you take it's picture.
This is an incredible shot of an amazing animal for the simple fact that it is underwater. Not all of us have the means nor the ability to get in the water the way you do to capture just the right moment with the creatures you've encountered.
This is a photograph that I'd not mind having on the wall by my computer or another room in my home.
I'm not sure how to judge technique as I'm not a photographer but it seems to be very well done. Originality I didn't rate as high only because there are other photographs like this taken by others. The impact is high because it drew me in from the very beginning. Vision is the same.
We've six turtles in our home. Reptiles are definitely creatures my family enjoys learning about and observing. I do have some photographs of them but not any captured nearly as well as you've done with this one. It amazes me that you've opportunities like this in your life wherever you go.
Croatia is a country where my parents were born so I've been aware of its attributes all of my life. I've been there a couple of times and wish to go back again one day. I don't think I'm so brave as to venture into the sea to take photos like this but the seashore offers up all sorts of landscapes and creatures enough to keep me happy.