I don't think there are very many tutorials out there like this one and it always seems to be a problem for people, SO HERE IS A REALLY CHEAPY, EASY, ATTRACTIVE-LOOKING tutorial on how to do fins for the seadwellers from homestuck!
I'll be doing a Feferi and a Condesce cosplay at Ikkicon this New Year's! So FINS!!!
Stay tuned and I will finish this tutorial with sculpting and backing for people who are looking for a more realistic look!
EDIT: HOLY SHIT YOU GUYS THIS ISN'T THAT DIFFICULT A THING AND NOT CREATIVE AT ALL WHERE ARE ALL THESE FAVORITES COMING FROM ;A;