---
title: Jellyfishes (Scyphozoa)
scientific_name: Scyphozoa
common_name: Jellyfishes
rank: Class
published: 2024-11-19T18:41:51.573Z
updated: 2026-08-23T21:14:20.368Z
tags: Jellyfishes, Scyphozoa, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/stinging/jellyfishes
---

# Jellyfishes (*Scyphozoa*)

## Quick facts

- **Rank:** Class
- **Scientific name:** Scyphozoa
- **Body shape:** Invertebrate - Not a fish - coral, mollusc, crustacean, echinoderm and other invertebrate groups.
- **Species listed here:** 8

## How to recognise this group

- gelatinous, often translucent, bell-shaped body
- rhythmic bell pulsations for movement or passive drifting
- multiple tentacles hanging from bell margin
- four or more frilly oral arms extending downwards

Nothing in the sea moves as cheaply as a jellyfish. The bell does not push water back the way a tail does; it squeezes, rolls a ring of water off its rim, and then stops working. The jelly springs back into its own shape by itself, and as it does, a second ring of water rolls in underneath and gives the animal a shove it never paid for. Gram for gram, no other swimmer covers ground on less energy, and it is done with one sheet of muscle laid over a slab of jelly.

Everything else about the body follows from having no blood. There is no heart, no gill and nothing to carry oxygen anywhere, so no living cell can sit far from seawater, and the tissue has to stay thin. The only way to be large under that rule is to be mostly water with a living film stretched over it, which is exactly what a bell is: the animal is the film and the rest is packing. Lift one into a bucket and it slumps into a puddle that dries to almost nothing.

This sea exported one of them. The nomad jellyfish is native here, and in the 1970s it turned up in the eastern Mediterranean, having gone north through the Suez Canal. It now swarms along the Levantine coast every summer in bands that run for kilometers, closing beaches and blocking the intake screens of power stations and desalination plants. Very few animals from this coast have had that much effect somewhere else.

And one of them gave up swimming. The upside-down jellyfish lies on its back on the floor of shallow lagoons and sheltered bays, bell down in the sand, frilled arms held up to the light, pulsing on the spot, so a bed of them reads as a patch of ragged brown coral until something moves. Swimmers over them often come out itching without having touched anything, because the animal lets small parcels of stinging cells go into the water around it. Of the ones that actually drift here, the mauve stinger is the one to recognize: small, purple, and painful out of all proportion to its size.


## Species (8)

- [Crown Jellyfish (Nausithoe punctata)](https://redseacreatures.com/taxon/invertebrate/stinging/jellyfishes/crown-jellyfish)
- [Crowned Jellyfish (Cephea cephea)](https://redseacreatures.com/taxon/invertebrate/stinging/jellyfishes/crowned-jellyfish)
- [Mauve Stinger (Pelagia noctiluca)](https://redseacreatures.com/taxon/invertebrate/stinging/jellyfishes/mauve-stinger)
- [Moon Jellyfish (Aurelia solida)](https://redseacreatures.com/taxon/invertebrate/stinging/jellyfishes/moon-jellyfish)
- [Nomad Jellyfish (Rhopilema nomadica)](https://redseacreatures.com/taxon/invertebrate/stinging/jellyfishes/nomad-jellyfish)
- [Orsini's Jellyfish (Crambionella orsini)](https://redseacreatures.com/taxon/invertebrate/stinging/jellyfishes/orsinis-jellyfish)
- [Purple Jellyfish (Thysanostoma loriferum)](https://redseacreatures.com/taxon/invertebrate/stinging/jellyfishes/purple-jellyfish)
- [Upside-down Jellyfish (Cassiopea andromeda)](https://redseacreatures.com/taxon/invertebrate/stinging/jellyfishes/upside-down-jellyfish)

---

*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/stinging/jellyfishes)*
*Updated: August 23, 2026*