Cymothoa exigua is a type of parasite that enters through fish's gills, eats their tongue, and then replaces it.
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There is a disease called ichthyosis that turns the skin scaly like a fish.
90
The seahorse is the only fish to have a neck.
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On some poorly researched trivia lists it is stated as a fact that a pregnant goldfish is called a twit. This is not true as goldfish lay eggs.
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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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