Bluebottle or Portuguese Man-O-War

Physalia physalis

This familiar species periodically plagues our coastal beaches, especially after strong north-easterly winds. The individual Bluebottle is actually a colony of hydroids known as siphonophores, each adopting a highly specialised function. The elongated float can grow to more than 150 mm in length, although rarely seen at this size. It has several long, thick tentacles used for fishing its prey, and these tentacles have stinging cells (nematocysts) similar to those found in most other species of Phylum Cnidaria. The sting causes severe local skin pain which may be followed by localised sweating, cramping muscle pains in all four limbs, cramping abdominal pain, respiratory muscle pain when ‘breathing in’ and anxiety. Tentacles from specimens washed up on the beach can also still sting. Treatment involves removing tentacles from the affected area carefully to prevent further envenomation, and application of cold packs or wrapped ice for relief of skin pain for 5-15 minutes. Seek medical advice if massive stings are experienced of if symptoms are severe.

Bluebottles are found in eastern and southern Australian waters, and also widespread in the Pacific and Atlantic Oceans.


Bluebottle or Portuguese Man-O-War (Physalia physalis), Wild Guide to Moreton Bay.

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