Learn Spanish (Latin America): El pescado está congelado.

To form the regular past participle of an -ar verb like congelar, you drop the -ar ending and add -ado. In this sentence, congelado is used as an adjective describing the fish. Because it acts as an adjective, its ending changes to match the gender and number of the noun. Here, it ends in -o to match the masculine, singular pescado.

Wait, isn't the word pescado also a past participle?

Yes, it is! Pescado is the past participle of the verb pescar (to fish). Over time, this past participle (literally meaning "the fished thing") became the standard noun for fish that has been caught and is meant for food. If the fish were alive and swimming in a river or tank, you would call it a pez instead.

Why do we use está instead of es with congelado?

We use the verb estar (here conjugated as está) because being frozen is a physical state or the result of an action, not an inherent permanent trait of the fish. When you use past participles as adjectives to describe how something is feeling, looking, or currently existing (like being frozen, closed, or tired), they almost always team up with estar.