A koi fish, named "Hanako", was owned by several individuals over many years and lived to be 226 years old, dying in 1977.
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Cymothoa exigua is a type of parasite that enters through fish's gills, eats their tongue, and then replaces it.
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Parrotfish make themselves a kind of mucus 'sleeping bag' which masks their smell from predators and keeps parasites away.
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Urechis unicinctus is a species of marine spoon worm that is widely referred to as the ‘penis fish’.
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