Originally Posted by ophiura
A real basic example of why that "rule" doesn't work is in something like the tank footprint. A standard 120 is a 4 foot tank. Would you really put all of those huge fish in a 4 foot tank?
So tank footprint, tank "purpose" (eg aggressive reef), filtration, adult size, territoriality, behavior...all manner of things blow the rule to bits. I think if you really think back to how you've selected fish, you'll realize that you are not sticking hard and fast to this rule, but take a lot of things into consideration.
I see what your talking about now, and I kind of feel foolish for thinking that was okay. I was just going by what I've read in several books... I would never put all those fish in a 4 foot 120, let alone a 180. I was just randomly thinking of different fish he COULD put in, I didn't mean to put them all in there.