CO 94, knit ribbing 1x1 for 7in
Beg inc 2sts by kfbf on K stitch before and after BOR marker (total inc 4sts) every 6th round.

Tail fin:
Fold half and pick-up CO sts to close the opening (mine, 45sts)
Sl1wyb (purlwise) kfb to last st, K1
Knit every row for 5.5in
Beg short rows as the pattern.
I love this construction of the tail fin, genius! Thanks to the designer, Jennifer Gelder.

My MODs:

1. Knit bottom-up instead of top-down.
2. Pick-up sts to close the opening instead of three-needle decrease.
3. Did 1 row of KFB instead to two because I already have 88sts.
4. Sl1wyb on every first st at the entire tail fin instead of sl1wyif on last stitch. Just my personal preference to achieve the same effect.
5. I used Icelandic bind-off at the tail.
6. Inc 4sts gradually on the body instead of drastically in a row.
7. 1x1 ribbing till waistline because I love it being stretchy
8. On knitting flat, transit my 1x1 ribbing to brioche knit
9. End with i-cord bind-off instead of V seed sts

The tail fin is the soul of this blanket though it is technically useless. And its yarn consumption is very high. Mine, 1 ball of 50g yarn gone for the tail. However, that part is the most beautiful part of the entire blanket. Another mermaid blanket is on the Q-list : )