That’s a tricky area, some people prefer to stock heavy and see no issue with it while some people prefer to stock lightly and see no issue with it. It all comes down to personal opinion at the end of the day. I believe that
Stanzzzz7
once said that a 75 gallon would be an ideal habitat for a couple apistogramma since they would show their natural behavior. I personally stock my tanks a bit on the heavier side and I like it that way. We are of two different opinions and could give two different answers on how to stock this tank for example and neither one of us would necessarily be wrong or right as it’s all a matter of personal opinion.
I hope I’ve answered your question to satisfaction.