Koi basking

Very nicely done.  I like the composition for the curving back towards us shapes, the swirling fins, set against the darker water background.  If there is space in original frame, perhaps a little more on our left?  The fourth fish under the tail is mildly unfortunate, but I don't find him to be overly distracting, and he is at least properly in line with the flow of the composition. The swirling surface water textures are a wonderful but subtle enhancement to overall composition.  Exposure may have given some noise, but it sure looks nice at this size.

Ry, the textures in the water surface and the positioning of the koi create a fine sense of movement.  I'm thoroughly enjoying the ephemeral trailing edges of the fins.  The exposure looks to be quite challenging.  In this case, the top of the back of the lighter fish is overexposed, which suggests shooting at -1EV, but a -1 EV would hide the detail in the darker areas.  Depending on your camera, you might be able to get away with -1EV with some dodging of the darks in post processing.  Two subtle improvements would be to burn-in the bright spot on the left edge a bit below center and cloning out of the bit of leaf in the lower left corner.

This is nice Ry. Good overall balance and color. They should probably be placed in the Man & Fauna gallery since they are captive.