まあじでわありませんでした
真鯵ではありませんでした
mājidewārimasendeshita

Noun
Desu Copula

The polite, past negative form of まあじ

1. Was not a true horse mackerel.; Was not a real jack mackerel.

Past/Perfective
Negative
Polite
Formal Register
Usually Written in Kana