El término pescado se aplica a los peces que han sido extraídos de su medio natural, para su utilización como alimento. El término pez se aplica a los peces que aun esta en su medio natural... aun viven en el agua.

Pescado: está muerto Pez: está vivo :)

Pez-stills alive Pescado- is dead, RIP lol

Pez= when still in their habitat, so you add the participle "ADO" at the end of the word, it which suggests that the animal has been PescADO or "Catched" in english, so, this word can be used in fishes: "I want Pescado for dinner" but also in people or things: "¡Hey, Look what I Pescado/caught!" or "I had Pescado/caught that guy" In the chlean Spanish Slang it can also mean "Pay attention" Oye! pescame! = HEY! Give me your attention!