ANSWER:

It is not mandatory to recite after al Fatiha. If you recite one ayah, this is permissible and if you don’t recite anything, this is also permissible. 

My question is what is the least amount of ayahs that we can recite in a single rakat during salah? Example if I want to recite the last two ayats of surah baqarah In one of the rakat of isha prayer is it permissible? Because I remember hearing from someone that minimum number of ayats in one rakat should be three.