Fido is neither a non-flying bird nor can Fido go underwater.
Every swimmer can go underwater. Everyone that eats fish they catch themselves is a swimmer. Every penguin eats fish they catch themselves. All nonflying birds in Antarctica are penguins. Fido is a penguin or a swimmer.
∀x (Swimmer(x) → GoesUnderwater(x)) ∀x (EatsFishCaughtThemselves(x) → Swimmer(x)) ∀x (Penguin(x) → EatsFishCaughtThemselves(x)) ∀x (NonFlyingBirdAntartica(x) → Penguin(x)) Penguin(fido) ∨ Swimmer(fido)