You will never see a 4' fish that lives in a 30" wide aquarium because the fish will be stunted (unhealthy) or die before it even has a chance to reach it's full size. That's what happens when you try to keep creatures that grow to enormous sizes in a tiny environment.
I'm curious, where do you draw the line? Is there a minimum tank size to keep specific species, or does the fish just have to suffer in whatever size tank you happen to have?
Never say never! The only reason you don't see a 4ft fish that lives in a 30in wide tank, because the owner doesn't want people like you to have a heart attack. There're 2ft arowana in 50gal tank, so it's not a surprise to have a 4ft fish in a 30in wide tank. I draw no line. The second I keep fish, I get off my high horse and not being so hypocritical to judge other fish keeper. Fish is suffer in whatever size tank you keep it! There's no such thing is minimum or maximum size of tank... Keeping gold fish in a 700+ gallon tank doesn't make someone better than other fish keeper. A fish in a tank is a fish in a tank. It's not the same as a fish in the lake or river. Isn't that why they prohibit to release fish that has been in tank back into lake or river? Use your common sense sometimes!
Neither you brag about your fish, nor share any idea. All you bragged was about how good the water without water change in 8 weeks, which to some of us is an insult, since some of us know how much waste and pollution those fish can create!

