Step 1:
The other side of this paper is pink. Other color combinations are also fine: Brown and yellow, purple and blue etc.
Prefold over these four lines.

Step 6:
Press these two places flat.

Step 5:
Fold both edges outwards.

Step 2:
Fold the four edges to the centerline.

Step 4:
Fold both corners to the inside.

Step 3:
Unfold the model.

Step 10:
Mountain-fold over the short white line.

Step 8:
Press both edges flat

Step 9:
Mountain-fold on the two corners

Step 7:
Fold over these two (curved) lines.

Step 16:
Pull / fold the tip downwards, make the same folds on the other side (see white lines).

Step 15:
Repeat step 13 on this part

Step 12:
Fold the edge to the inside of the model.

Step 11:
Fold the model in half.

Step 14:
Repeat step 13 three more times

Step 13:
Press these two spots against each other by folding over the three lines. Do the same on the other side.

Step 18:
Press the nose flat (except the tip of it) and fold both fins sidewards, see white lines.

Step 17:
Fold the tip to the inside.