The fluke in the pic is definitely the "She-Creature" fluke and thus far it has not been an option available to the public / is one of her personal tails. Raina's tail, I believe, has the unofficially nicknamed "calypso" fluke and was also the same fluke shape on the Rainbow Mantis shrimp inspired tail and I think on Raven's recent lionfish tail. That said, she does do custom fluke designs for an extra fee if none of the current offers suits your tastes.