Being a jellyfish is not enough is the 1st EVER episode of the season 6 of Teletubbies (2015 TV series), and the 177th episode overall.
The episode starts with a purple mollusc without shell which transforms into a purple jellyfish with Tinky Winky's antenna. This purple jellyfish go behind some algae. Then the purple jellyfish find red, yellow and green molluscs without sheel (to mean Po, Laa-Laa and Dipsy). When the purple jellyfish touch all the molluscs, those last transform into jellyfishes. Some (millions of) years later, when all the jellyfishes got bored, they decide to transform to fishes.
The parents liked this because there was no violence, no blood, no guns. The kids disliked it for the same reason.
- This happened in 650 before Jesus-Christ.