Räikkönen no Nettaigyo

Sekohara finds himself joining the Tropical Fish Club at school, which at this point, only has the founder as its only member, a mysterious girl named Räikkönen. She is a self proclaimed witch, but Sekohara doesn't believe in the nonsense until she is able to turn an angelfish into a human girl with the use of her homunculus alchemy. Räikkönen's goal is to see what happens when a human mates with the transformed fish, but the more time Sekohara spends with Räikkönen, the deeper the emotions get....