8.0! That it high! I doubt those neons will like it that high! The Ph inside the tank is most likely going to be at least 8.5, and although adaptable, neons will prefer a lower Ph (7.5-6.0ish)! I recommend taking that rock out asap. Besides, it doesn't suite the tanks atmosphere anyways
Neons will live in high ph its just they won't breed in it.
Ive had mone for nearly a year in a ph of 8.5 and are still ok.
Because they are tank bred, they can with stand a variety of diffrent water chemistrys. Just because they can live, doesn't mean they will thrive...