The article "Daily Rhythms in Cnidaria" by Bora Zivkovic explains how cnidarians have a biological clock and how it differs from other animal kingdoms. Jellyfish, corals, and sea anemones are in the same animal group because they have complex life cycles with different stages. Sometimes the rhythm of the different stages is synced with the moon. It is unknown if the environment affects their rhythm or if it generally biological. The article discusses the several stages and the rhythms of different cnidarians.

The article was from 2012 so there could be newer information.


Daily Rhythms in Cnidaria