I have a little experiment going at the moment .
I have a very heavily planted tank about 20 gallons with the following ALL living happily !!
Every fish is very young and under an inch in length .
2 Apistogramma panderini (pair)
2 Apistogramma pulchra (pair)
2 Apistogramma cacatuoides (pair)
2 Borelli Cichlids (Pair)
2 Keyhole Cichlids (pair)
4 Checkerboard Cichlids (tiny)
The only two fish who had a problem with each other was the female panderini and the male pulchra but they took it in turns to "chase" each other .. ... there was no outright winner so they both get on with each other ( well tolerate each other ).
=Amazingly the only fish who has claimed a little patch of tank is one of the TINY checkerboard cichlids
I realise that this tank is only peaceful because they are ALL such yopung fish but it is fantastically intersting to watch them all going about their business.
As they grow I will simply move them to other tanks.[/u]