The turritopsis nutrivacula jelly fish is biologically immortal...

You might want to know how old the oldest immortal jellyfish is, but unfortunately there is no answer to this.

No turritopsis dohrnii has been observed in a laboratory for an extended period of time, and there is no other way to establish the age of an individual.

The process that lets the turritopsis remain immortal is called transdifferentiation and it involves one cell converting from one type to another.

Thus, when the jellyfish reaches maturity, its cells can convert and it becomes a polyp again.

They are only biologically immortal, they still can be eaten by predators (and they certainly are eaten).

The immortal jellyfish prefers warmer waters, although it has been spotted in colder areas as well. They originate from the Caribbean Sea (nutricula) and the Mediterranean (dohrnii).

Their diet consists of plankton, fish eggs and small mollusks.

If you want to spot an immortal jellyfish in the ocean, be aware that it is barely visible. The turritopsis dohrnii is bell-shaped and it is at maximum 4.5mm (0.18 inch) tall and wide. They are tiny creatures. Younger turritopsises have only 8 tentacles and are 1 mm tall, while adult ones can have up to 90 tentacles.

Its large stomach is bright red colored. In its polyp form the dohrnii is made up of stolons and branches that can create medusa buds.