I don't agree with that and it is the best rock you can have for any African Cichlid tank.. PERIOD..... It has so many good benefits to it for them from the PH buffer and all the holes it has for them to hide in to the way you can stack it up to make caves and hiding places, And it just looks AWESOME if you do good WC and keep it clean... But the most important part is your fish will love it, and that is why we do this right???