Translation of "Mirage" in Japanese

A mirage is said to be an illusion.

蜃気楼は幻影だと言われている。

A mirage sometimes shows up in Toyama Bay.

富山湾にはときどき蜃気楼が現われます。

Which makes me think it was definitely a mirage.

あれは しんきろうだったんだ

And that just makes me a little bit suspicious whether maybe, the oasis is really a mirage.

オアシスが しんきろうだったのか 少し不安になるね