Explanation: You cannot just say Iophobia because the word needs an ending in itself, like -ophobia. This noun, the moon's name, ends in -o. It must be expanded in some direction. Compare, Pluto, another name ending in -o. Is the fear of Pluto called plutophobia? No, it isn't, it would be something like Plutonophobia.
Hence, Iotophobia.
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Finn. Male. Older than you. Me and my cat.