I read another Surah after Al-Fatiha in the last two Rak'ah of the fourth prayer. Is that acceptable?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

It is more proper to avoid reciting any portion of the Qur'an after al-Fatiha in the third and fourth Raka'h of al-Zuhr, al-Asr and al-Isha prayers and in the third Raka'h of al-Maghrib prayer. This is the opinion of the majority of Muslim scholars, since most narrations of the sound Hadith of the Prophet (Sallallahu Alaihi wa Sallam) bespeak the above-mentioned opinion.
It is recorded in Sahih Muslim and Sahih al-Bukhari from Abu Qatadah (Radiya Allahu Anhu) who said that: "Allah's Messenger (Sallallahu Alaihi wa Sallam) used to recite al-Fatiha and a Surah of the Qur'an in each one of the first two Raka'hs, and only al-Fatiha in the third and fourth Raka'hs while performing al-Zuhr prayer. And he (Sallallahu Alaihi wa Sallam) used to make us hear the verse sometime, and to be lengthy in the first more than the second. Also, he used to do the same in al-Asr and al-Fajr prayers" .
Anyway, if a worshipper recites some portion of the Qur'an in the third and fourth Raka'hs after al-Fatiha, it is permissible since it is reported in Sahih Muslim that the Prophet (Sallallahu Alaihi wa Sallam) did so.
Allah knows best.