Yeah with SA and CA cichlids it's best to under crowd while with African cichlids it's better to over crowd then under crowd. Angels and keyholes are SA cichlids if I'm remembering correctly so it would be better to have more space and less tank mates. The original 5 angels, 2 pairs of keyholes and 10 lemon tetras would be best to stick with. Apistogrammas tend to do best in specie only tanks as they tend to be very aggressive for such a small size.Oh, that was just a thought, if it wouldnt work out then I guess I need more tanks? If only the mother agreed.
I agree with this, a 75 is in reality, a fairly small tank, and the angels, and keyholes with dither fish are plenty for that space, especially if they are now, all young.Where did the apistos get added into the equation? Keyholes and Angel's are more than enough cichlid for a 75. Cichlids need territory and typically territory means floor space as well as water space. 2 pairs of keyholes will claim most of the bottom when spawning. Truly with keyholes, tetras, and the angels the tank is pretty much full as far as territory availability goes.