this would be nice to have to show people at the store what there buy because they normaly they dont research befor they buy. some of these are good fish to own even with there large size but some just get way to big and aggresive. ever see a african goliath tiger fish eat its unreal so much more aggresive than a snakehead. its nice to see these fish but most people dont give them what they require to thrive.
Torpedo barbs/roseline sharks get alot bigger than most people think, 6+ inches, and are not uncommon in stores.
I was at a local store in Mobile, AL a couple weeks back and they were selling 3 18in baby alligator gar for $40. ALLIGATOR GAR!!! That is ridiculous, they get almost 200lbs and 7+ feet long! I have been bowfishing for these guys in Mobile Bay and they def don't belong in home aquariums. But rest assured somebody will cave in because they look so awesome and buy one, or two , or three...
Also, someone posted earlier that arapaima gigas reaches 5m in length, pretty sure thats a big overshot. Maybe 4m at the absolute most, and even then still not the biggest freshwater fish. Mekong giant catfish/stingrays and some sturgeon get significantly larger.