It could have been... if you just got it and he wasn't alimented right. was it a dwarf gourami?
dwarf gourami's are specifically bred to be small and are disease prone
I have kept normal gourami's in the same ph for years with out any problems. one of my current gourami's is seven years old.
if it was a dwarf gourami then that could be your answer if their isnt anything else as like said previous are prone to disease and infection. but i wouldnt mess with the ph leave it if its stable!