Requirements to find a non-common pet

[Menschlein]

I've tried to find a solution in the forum but only found different informations for my problem

Do i need to beat rare or super rare pets like Mesmerit or the Weekendpets in the habitat first? Or is it possible that i can find them even without beating them first?

Please dont be mean if i overlooked a fitting answer^^

[LapisUlami]

You have to beat the habitat first.