Rockpool Rambles with Backyard Zoology

One of the most underrated tidal pool inhabitants is the good ol’ anemone. If you’re anything like me, you’ll give the anemones tucked into nooks and crannies a bit of a cursory glance and then move on. I’ve been trying to right my wrongs lately and be an equal opportunity rock pooler, and have been giving them the love they deserve. As a result I’ve gone and fallen in love (and, incidentally, actually fallen hard on the rocks) with the swimming or wandering anemone, king amongst all anemones. Here’s why.

They might look like plants, particularly flowers with their tentacles unfolding like brightly coloured and often patterned petals, but anemones are animals. And predatory animals at that. Their tentacles are covered with stinging cells and they use them to catch prey and then to move it to their mouth. Mostly you’ll see anemones attached to rocks in the intertidal zone, but if you spot a swimming anemone (aka a brain anemone, for obvious reasons. I mean, just look at it!) it’ll likely be rolling along the sand or attached to some weed.

Swimming anemones (Phlyctenactis tuberculosa) are the largest anemone commonly found in local rockpools, growing up to 25cm. Sure, you’ll find itty bitty baby ones too, but if you see an adult, you’ll know it. They’re absolutely stunning and range in colour from shades of red, to green, orange and even mauve, making them really stand out amongst the weed that they’re often attached to.

They do get referred to as baked beans and, with their tentacles tucked away during the day and their bubble-like sacs on display, I kind of get it. And if that means that I find baked beans stunning, so be it. These anemones are nocturnal and they use the night to move around to feed.

The common name ‘swimming anemone’ is a bit misleading as they don’t swim as such. They can easily detach themselves from whatever substrate they are on and either rely on the tide to roll them across the shallow seabed or using their basal disc they’ll crawl along and even climb up weed where they will wait, tentacles unfurled to catch prey.

If you’re zooplankton, watch out as you’re on the menu.

If you’re a curious human with a tendency to touch all the things, you should also watch out, as unlike baked beans, these anemones can give you a nasty sting.