Considering that for most "hardcore" fish enthusiasts, a big tank would probably run somewhere between 100 and 225 gallons, what would be the biggest (excluding oddballs like eels) fish (adult size) that would be ethical to sell? Personally, I think that it is unethical for places like Petsmart to sell even Oscars since I imagine most of the people that shop there don't take the time to really learn or care for their fish properly. I am all in favor of capitalism, but couldn't the fish community pressure places like Petsmart and Petco (I will say that Petco, at least in my area, seems to be stocking fewer big fish in favor of barbs, tetras, etc) into selling "responsible" fish to their "Irresponsible" customers? Certainly, with the impact of the internet, the fish magazines, the various local clubs, etc, there could be some form of lobbying group going to these companies and pressuring them to be more responsible. Maybe big species should be exclusive to actual tropical fish shops? And how about the modified fish that they tattoo and cut their tales off, etc? Horrible. If what happens to tropical fish were happening to dogs and cats Peta and everyone else would be all over this, and they should! So why are fish somehow different? Just some thoughts. I do wonder, what is the biggest fish species that you think is a responsible fish for a serious owner to have in say a 150 gallon tank that has a base of 6' x 2'? And also, what should be the biggest fish species that places like Petsmart should be allowed to sell? Just wondering what thoughts are out there on this... Of course goldfish throw a serious bind in my question don't they? Potentially 3'...