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  • Writer's picturerichelletanner

FYI: clownfish don't have seizures

My search history often reads like a random word generator. Highlights from this week include "clownfish uncontrollable shaking", "dissolved inorganic carbon cycling", and "best plants for apartment gardening". Sometimes I wonder what Google thinks I do. While the first month of grad school has been a whirlwind, I never expected that I would become a surrogate fish mother while my officemate taught a course in Mo'orea for the semester.

The tank itself is impressively backlit by fluorescent aquarium lights that show off the brilliance of his pink corals and baby giant clams. Hermit crabs and limpets mill about and anemones sway in the flow, but the main attraction is the fish: Emilé and Ava. Clownfish are hermaphrodites, meaning that they can switch their genders. The sex ratio in clownfish populations is driven by size - the largest fish is always the female. While Ava and Emilé began at the same size, Ava is clearly the female now. She's not afraid to throw her weight around - both with Emilé and humans. So when I walked into the room one day to find Emilé on his side, twitching like a wind-up toy, I feared the worst. Neurological disorder, parasite, malnutrition - these were all things running through my head as I braced myself to write to my officemate to say I had somehow killed his beloved Emilé. After sending one or two (or six) frantic emails, I turned to Google to try and figure my way out of this disaster.

It turns out that this horribly unnatural-looking behavior is the topic of hundreds of aquarium hobbyist threads, all of which describe it as I did - a "clownfish seizure". But instead of being a life-threatening condition, it is actually a tactical behavior. If you remember back to the sex ratio determination in clownfish populations, males are always smaller than the female. Since the female rules the roost, the male clownfish behave in this erratic way to show that they are submissive, or not a threat. It is completely normal, although I would imagine it isn't the most comfortable behavior.

So the next time you watch Finding Nemo, just remember - when Nemo's mom dies, Marlin would have become female and Nemo would have been stuck with his "seizures" and wouldn't have had time to get himself kidnapped by an Australian dentist. The more you know.

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