Upside down jellyfish are a rather unique jelly. Unlike other
Jellies, that float and swim around wherever the currents take
them, these jellies have decided to check out life from another
angle. They have tipped themselves upside down (hence the name) and
settle their tentacles up, resting their bells on the ground. They
are usually found in calm shallow water, such as shallow lagoons
and estuary areas in tropical waters. Often they are found in
extremely large numbers, completely carpeting the bottom of lagoons
with hundreds of little pulsing bodies.
Many people have an instinctive fear of anything 'jellyfish' due
their renowned stinging ability. But while a blue bottle can give a
nasty sting and box jellyfish can be deadly, not all jellyfish will
cause serious harm. The moon jellyfish, for example, is completely
harmless. The upside down jellyfish will not give a painful sting,
but they do still have stinging cells on their tentacles, so
brushing up against these can leave an itchy rash. Moral to the
story, if in doubt: Don't Touch.
Like all jellies, upside down's have a polyp phase of their life
cycle, during which they look like a small anemone attached to the
ground. From this polyp, little "baby" jellies, called ephyra
"bud" off the end of the polyp starting the next phase of their
life cycle as a swimming medusa, looking like miniature adults only
a few millimetres across. Feeding on tiny plankton, these babies
quickly grow larger, until you have jellies about 20cm (like ours
on exhibit) which have striking blue and brown colours on their
bell and white tentacles.
Interestingly, as well as feeding on zooplankton, this jellyfish
also harbours a photosynthetic algae found in the green leaf like
stalks stretching up from within their arms. These algae harvest
sunlight, just like their cousins in corals and the jellyfish can
use this energy to grow faster.
You can see these incredible animals at SEA LIFE Sydney Aquarium's
new Sydney Harbour exhibit.
Pre-book your tickets to the new SEA LIFE Sydney Aquarium and be
one of the first to see all the new developments and SAVE!