Extract from ‘Bring on the Clowns’

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Foreword by Nathan Hill…

Jeremy Gay used to be the editor of Practical Fishkeeping, and a mentor to myself. He’s a man who can handle his words, which explains why he’s also the author of one of the world’s best-selling fish books ever. He’s hands-on, frequently irreverent and often blunt to the point of being brusque, something that occasionally shows up in his writing, as though he doesn’t even suffer the foolish reader gladly.

He’s also a delight to read, because behind the shortness of patience, there is a reverence for the natural world and a passion for fish that glows like lava.

The below extract is from Jeremy’s feature on clownfish for the March 2020 issue of PFK. Here he speaks of the clownfish’s famed ability to live within the deadly, stinging and adhesive tentacles of sea anemones…


“Clownfish and anemone symbiosis is mutually beneficial. The stinging cells of the anemone protect clownfish from large, predatory fish, and the clownfish in turn protect the anemones from Butterflyfish, who don’t mind the stinging defences, and dine on them.

Anemones also benefit from the extra aeration and nourishment from clowns, and many a captive clown and ‘nem’ keeper will observe a clownfish retrieving food for its host, and clearing the area around it of algae and rival coral growth.

There is no consensus on why the clownfish doesn’t get stung by the anemone. Some theories are that the fish’s mucus camouflages it against the anemone. Others are that the fish smear themselves with the anemone’s own mucus, making them invisible. One hypothesis said that clowns had neutral mucus, where other fish had acid mucus. Another said that clownfish mucus thickened upon contact.

One train of scientific thought was that clowns could customise mucus chemistry to decrease the synthesis of substances which excite the anemone’s nematocyst discharge. Another was that clownfish mucus is based on sugars rather than proteins, and lastly, that clownfish are just naturally immune to anemone stings, though this has been disproved.

Whatever it is, the anemonefish/anemone mutual relationship is obligate, and science has shown that Clownfish do not survive in the wild without anemones, and for the ten host anemone species, they cannot survive without clownfish. Which makes you think a bit more about the effects of wild collection; if one were collected without the other, the organism left behind would face death if a new localised pairing could not be made.”

The full article can be found in the March 2020 issue of Practical Fishkeeping, out on January 22, 2020. If you don't already, subscribe to our digital magazine HERE.