Perhaps not, but no doubt there are individuals with medical training. [L-like a Pokecenter maybe?] They may be able to offer help... provided she is sick.

[Ah. He can see it, Xiaoqiao! Other than the shimmer, nothing really stands out as wrong. The fish itself doesn't appear to be all too bothered - there's certainly no lack of energy. Fingers crossed it just doesn't suddenly drop dead or something. (How morbid!) Because otherwise, there doesn't seem to be a problem.]

Have you considered it may be natural for this species? Most insects undergo multiple physical changes during their lifecycle. Although they are not fish... it is not something exclusive to insects alone.

[You know, it's amazing how this is their third meeting and it's the first time he's referred to bugs. The spell is broken!]