I was informed that the isha prayer needs to be done before 12:00 midnight. Is this true?

The time of Esha Salaat ends at Subh-e-Saadiq (true dawn), i.e. when Fajr time comes in. (Tahtawi pg.178)

However, it is Mustahabb to delay its performance till just before 1/3 of the night has passed. (Tahtawi pg.184)

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai