Both mine are afraid of everything so they dont grow as they should, 7-8" @ something like 5 years old, the other is maybe 4.5" at the same age. I think they are slowly learning to stop being afraid of other fish.
sir, pangasius is a family name. each species from the genus varies in size and growth rate.
the most commonly sold in the FS are iridescent shark/pangasius hyphothalamus(i think i my memory serves me right) and the ever famous paroon shark/pangasius sanitwongsei
they do look alot like coloration and stuff but the paroon has pointy and long dorsal fin.
ouch, good thing I gave it away on craigslist to some guy with a 400 gallon.
I ended up buying some discus from a friend and got back in to discus, after give the tank a cleaning.