Definition: Given a disfluent sentence, modify the sentence to it to its equivalent fluent form, preserving the meaning of the sentence.
Input: What do Euplokamis stationis or actually I mean Bathyctena chuni and Euhamphaea veilligera only produce when they change color?

What do Bathyctena chuni, Euplokamis stationis and Euhamphaea veilligera produce only when they change color?