A tank that big with that few discus, will generally result in stunted discus. Discus can stunt by poor water parameters, and not enough, or poor quality of food. However, they also stunt from burning off too many calories.Loubard;1478841;1478841 said:20 in a 180 is really really to much, they need there space. I would get 6/8 max. for a 180. You will really be able to enjoy them more because they got the space to act natural. Get some bogwood wich they can stand under for them as well, they will really thank you for it by being more active as they feel secure.
WyldFya;1481686; said:A tank that big with that few discus, will generally result in stunted discus. Discus can stunt by poor water parameters, and not enough, or poor quality of food. However, they also stunt from burning off too many calories.
I'd recommend at least 18, but you could pretty easily do more, if you setup the tank with auto water changers, or just water change very regularly.