The koi fish symbolizes a bunch of good things (strength, prosperity, good luck, yadda yadda) in some Asian cultures, and a gold colored koi specifically symbolizes wealth and prosperity. With or without money, whipping out this clip from your pocket allows you to keep it classy while taking a fish out of your pants.
Step 1: Make fish outline
Find a picture of an uncontorted koi fish online. Put this picture in the background of the 3D viewer on Blender. Add a plane, delete three of the points on the plane, and extrude the point (Ctrl + LMB) as many times as needed to draw the outline of the fish. Close the fish outline by selecting the first and last points only and connecting them (F).
Step 2: Fold it in half
Select two vertices from the fish outline and connect them (F) to make a line through the fish between its ventral and anal fins.
Select both points from the line formed above and all points on the tail end side of this line. Put the 3D cursor on the line formed above and rotate all highlighted points 180 degrees along the Y axis (R, Y, 180). With the vertices from the tail end still selected, grab and move them all down the z axis (G, Z, # and direction of units).
Step 3: Insert eye
On the front half of the fish, place the 3D cursor where the eye would be, and add a mesh circle on the same plane as the fish body. Scale to a reasonable eye size.
Make numerous faces for the front half of the fish, making sure to keep the eye hole open (select desired points, F).
Step 4: Extrude fish surfaces
Select any points that got mangled with the previous rotation and delete them. Select all points on the tail end of the fish and close the surface (Select vertices, F). Make sure the top and bottom halves of the fish are both closed surfaces.
Then, extrude each half of the fish along the z-axis (select appropriate faces on each side, E, Z, # units and direction for extrusion).