for a 30Gal, I would say possibly 1 male and 3 females.
Apistos are bottomw dwellers, occasionally hovering about the middle section.
You could get some smaller tetras or rasboros (I'd say 8 in a 30gal).
But I would read up on cichlids, dwarf species and get to know them, as there are many types of apistos. You have to take tank temps and water hardness/softness into account too.
There are more experienced keepers on this forum, that I am sure will come along and give you better advice, than myself.