There´s two things that caught my attention so strongly, but first the complement:
AMAZING! What a detailed and dynamic artwork you did there, it really looks real, wow! ^ ^
So here´re the two things: The splash effect of the water while he´s running, very convincent, with a lot of movement and good strokes, really amazing. And his skin, mostly his scales, the coloring selection is really good and impressive, it gives a convincent texture by only watching.