8 Tail Flutes

In this context a 'flute' is a groove, the bottom of which is rounded. But here's the important thing: we're really interested in the ridges between the flutes. We want these ridges to run smoothly and fluidly, like the fish. We also have to match the flutes on either side of the tail fin and imply a sense of how it attaches to the body,

For the sharp-eyed among you: Yes, the block underneath the carving taking the strain does indeed have 'banjo support' written on it. When I change strings on my frailing banjo, I rest the neck on this padded block and it just happened to be at hand.

 Who'd have guessed that a Koi and a banjo could have so much in common...