small alien
The fungus is among us.
I think you are being too sweeping in your statement. Further, chromis may very likely have more bioload per fish than many other small gobies, etc. I currently have 14 fish in my 75. And I plan to add a couple. It has so much to do with which fish and what parts of the tank they occupy in addition to bioload issues. How many fish is just really not that great of a question. Its more subtle and complex than that.