Download Mobile App: Android Download Mobile App: Android

Blue Button

It has a blue float made of a flat, circular disc with many gas-filled tubes which keep it afloat. The disc is surrounded by tiny blue tentacles.

The Blue Button is, in fact, a colony made up of different types of polyps, including some that are specialised for catching food, defense, or reproduction.

Size

Its disc is up to 2.5 cm across.

Behaviour

Diet

Small marine animals such as copepods, crab larvae and tiny fish fry. Its tentacles kill prey with their sting and then move the food to its mouth, which is on the underside of its disc.

Movement

It floats freely in the water, and is moved along by ocean currents and wind.

Breeding

They are hermaphrodites (i.e. both male and female). The specialised reproductive polyps release both eggs and sperm into the water. When the eggs have been fertilised by the sperm, they develop into larvae that subsequently metamorphose into individual polyps. A Blue Button colony forms when one polyp divides to form new types of polyps which become specialised for different functions.

Field Guide

Improve your identification skills. Download your Blue Button guide here!

  • Species Category: Marine
  • Species origin: Other
  • Conservation status: Common
  • Did You Know?
    • The sting from its tentacles is not known to be dangerous to humans
    • It is often found floating with the Blue Sea Slug which floats upside down

  • What to Observe

    • Presence (to establish the first and last sighting of the season)

    Climate Adaptations

    We don't yet know whether water temperature affects where jellyfish are found. Data on their distribution will help determine whether their range is changing and how climate change may impact their distribution.

  • When and Where

    When To Look

    • All year round
    • Particularly in warmer months, around summer time

    Where To Look

    • On the surface of coastal waters around Australia
    • Often washed up in large numbers
    • Common on exposed ocean beaches after strong onshore winds have blown it in from the tropical north

  • What Else?

    Similar Species

    Blue Bottle Jellyfish (Physalia utriculus) has an air sac for a float and long blue tentacles which can be up to 10 m long whereas the Blue Button's tentacles are short.

    By-the-Wind Sailor (Velella velella) doesn't have any tentacles fringing its disc and does have a sail sitting upright on its disc.
  • Trails: Bellarine Peninsula - Barwon Coast & Ocean Grove Nature Reserve VIC, Cape Conran VIC, Killalea State Park NSW, Randwick Coastal Walkway NSW, Ricketts Point VIC
  • Species Region: Australia