What a big fish!

No, I don't mean that! Demon means a bad guy or villain... The HELL IS THAT FISH!?

She means she caught the wrong fish.
(The ships are talking about the word "Gedou" which means multiple things. In this case, Nisshin is calling the Abyssal demon, one interpretation of the word. But Hibiki misunderstood Nisshin's use of the word "Gedou" to mean "an unintentionally caught fish.")

Demon?

Damn demon!

Ow ow ow ow... For how long are you gonna attack me?