My headcanon on the Hetalia girls in general!
Erika hates being called an child, because it makes feels self conscious on her childlike body, despite having an fine pear shaped body.
She has an strong fear of the ocean, strong currents and fish, because of the countless flooding in her history, as well as untrained or violent tempered dogs. Though her biggest fears would being abandoned.
She's also scared of fish, too. She's gets crept out by it's odd shape and weird eyes. She'd probably have an panic attack at the sight of one. Seafood is is definitely her least favorite food.
However, she does know the difference between real fish and cartoon fish. Like she'd really cool around Nemo.
She has some faded burned marks on her feet from her being almost burned alive after being accused on being an witch during her country's witch hunt that took 10% of her population. Erika doesn't remember who rescued her, but she does remember waking up with an relived nurse.