どくじゃなかったです
毒鱓じゃなかったです
doku janakattadesu

Noun
Desu Copula

The polite, past negative form of どくうつぼ

1. Wasn't poisonous.; Wasn't a pufferfish.

Past/Perfective
Negative
Polite
Casual Register
Usually Written in Kana