Morbakka fenneri: Moreton Bay Fire Jelly

Species profile · Last reviewed 22 August 2026

Morbakka fenneri, often called the Moreton Bay fire jelly, is an Australian box jellyfish associated with Irukandji syndrome. It is visibly larger than the tiny species that shaped the original “Irukandji jellyfish” image—one reason the syndrome should never be reduced to bell size.

Appearance and identification

The animal has a tall box-shaped bell and four tentacles, one at each corner. Colour and size vary with condition and preservation. Confirmation relies on anatomy and locality; a photograph alone may not separate it from related carybdeids.

Known Australian range

Records include eastern and northern Australian waters, with the common name reflecting Moreton Bay in Queensland. Exact seasonal presence varies by location, and a species record is not a beach forecast.

Medical importance

Stings have been associated with Irukandji syndrome: delayed severe pain and systemic symptoms that can include sweating, nausea, agitation and cardiovascular changes. An initially modest skin mark does not rule out serious illness.

Why this species changed the conversation

Early public descriptions emphasized tiny, almost invisible Irukandji jellyfish. Morbakka fenneri demonstrated that a substantially larger animal could produce the same clinical syndrome. The more accurate framework is therefore “syndrome associated with multiple species,” not “one tiny species with one appearance.”

Sources

• Australian Museum: Morbakka fenneri and Irukandji syndrome
• Healthdirect Australia
• World Register of Marine Species

Medical content is editorially source-checked; independent clinical review is pending.