This is very true. I agree with Moon that the best possible sturgeon for aquaria are Shovelnose. relatively small species, wide temperature tolerances, and easily adaptable to home life. unfortunaly, they are all but impossible to locate and purchase for the average aquarist (and even the above average, as i have done my share of hunting and came up empty handed)
Having kept "Sterlets", "Daimonds", as well as recently White sturgeon, i can say that even if you can locate and house these fish, if they are purchased at a small size these fish make the most fragile freshwater fish look like mike tyson. think black arowana on steroids
i can only compare the amount of food these fish consume at small sizes to that of a juvenile himatura sp. ray. and a fingerling african arowana combined (having raised both to adulthood). without a nearly constant food supply there is not a chance in hell of these fish surviving. they have incredibly fast metabolisms at cooler temperatures and even faster at the unchilled temperatures most aquarists manage. I feed my fingerlings constantly with a mix of frozen mysis shrimp and blackworms (at least 7 times a day) as well as seeding the sand with blackworms for them to forage for.
that being said, once these fish reach about 8"s they are pretty damn hardy. i kept my last large one with an emperor cichlid and longnose gar.
if you want to devote the time and effort into these fish i wish you all the luck in the world....keep me posted on your success. i hear very few stories of aquarists successful with these fish in a captive environment.