^ I know EXACTLY what you mean, especially when walking around MK shopping for fish and hearing the shop keepers tell people they can keep a few alligator gars in 10G tanks and stuff like that...
Although with that being said, i must say most of the shop keepers don't seem to actually know much about the fish they sell, considering the amount of GSP's of all sizes that are always said to be able to live out their lives in F/W with no problems, or selling fish when they are young and saying they don't grow bigger than 2 - 3 inches when infact they grow to like 2 - 3 FEET in reality
Which just goes to show why its so important to do your research before you buy fish, especially in a place like Hong Kong...
P.S. to the OP, sorry for hijacking your thread, but i'm just amazed to see other members from HK on this site...