Is Lieblingshaustier der, die or das?

The correct German article for Lieblingshaustier is das. The noun Lieblingshaustier is Neuter. So you always say: das Lieblingshaustier. Learn the article together with the noun — German nouns don't follow predictable gender rules most of the time.

The plural of Lieblingshaustier is: die Lieblingshaustiere. In the plural, every German noun takes the article "die". So: die Lieblingshaustiere. Example: ein Lieblingshaustier → zwei Lieblingshaustiere.

Correct: die Lieblingshaustiere. The form "die Lieblingshaustiers" is wrong. The plural of das Lieblingshaustier is die Lieblingshaustiere. In the nominative plural, you always use the article "die".

das Lieblingshaustier follows the four German cases. Nominative: das Lieblingshaustier, Accusative: das Lieblingshaustier, Dative: dem Lieblingshaustier, Genitive: des Lieblingshaustiers. In plural: die Lieblingshaustiere / den Lieblingshaustieren. Learn these forms together with the noun.

The genitive singular of das Lieblingshaustier is: des Lieblingshaustiers. The genitive plural is der Lieblingshaustiere. German uses the genitive to express possession or belonging. Example: die Farbe des Lieblingshaustiers.

The dative plural of Lieblingshaustier is: den Lieblingshaustieren. In German, dative plural nouns usually end in "-n". So you say: "mit den Lieblingshaustieren". Use this case after prepositions like mit, von, bei, zu.

Lieblingshaustier is a noun and must be capitalized in German. You'll find example sentences above for each case. The article das stays the same in nominative singular but changes in other cases. Practice declension in your own sentences.

Yes, Lieblingshaustier is a noun (also called a substantive). German nouns are always capitalized. The article for Lieblingshaustier is das. Every German noun has a fixed article you must memorize.