I enjoyed the reading. I like the fact that some fish have their "place" in the tank. I think if one is adding fish to a tank that it is good to re-arrange. Years ago I had two rainbow cichlids with some convicts, they were all getting along and then one day one of them killed the other and then went on terrorizing all the convicts. I put it in a 10 gal until I could trade it to the LFS. I am sure this is an example of ATS, it just freaked out one day.
Keep the aquarium stocked. If an aquarium that is meant to have many fish is allowed to sit unused save one or two fish, then those one or two fish will most likely suffer from ATS in that they will be alone for so long that they will think the entire tank belongs to them.
Lastly, if feasible, buy an aquarium that is a size larger than is thought necessary. Sometimes, especially if ATS actually does occur, the best solution is to keep the problem fish with other fish that are bigger than itself. If the tank is small, then this option will not be available to the aquarist. Additionally, a large tank affords the aquarist more stocking opportunities than smaller tanks.
These concepts seem to almost counter each other. I think they are pretty broad statements and really have to do with the type of fish that are being kept not so much tank size and population.
I can see how you would find them contradictory, but they are not. They are broad, but still germane:
Keep the aquarium stocked. This means that whatever stocking level you intend for the tank to have should be the level it is kept at.
Buy an aquarium that is a size larger than is thought necessary. That is, do not necessarily stock more or less, but make sure that the environment is large enough to accommodate larger fish than what you plan on keeping. For example if the largest fish is supposed to have a tank 30 inches long, go ahead and try to get one 36 inches long. This statement is not necessarily talking about stocking density.
These are actually good practices (in my experience) for all occasions, regardless of species kept.
