Why thank you- But be careful about letting her hear that. [Strange warning, perhaps, given Mami's smile and the fact it's a compliment. But there's no denying that - having heard it - Trista does a one-eighty in the water, making a small way to... strike a pose.

You can practically hear the proud, laughing "Oh, go on!"

But Mami doesn't plan to, ignoring Trista in favor of question answering.]

That's very kind of you. Some types do prefer to stay in their form, I hear, so I'm sure she appreciates it.

But if she does want to evolve, you need to exchange her, with an item called "Prism Scale" attached. It doesn't have to be for good- But trading with another trainer even temporarily should trigger an evolution.