The largest pangasius suchi (I.D. shark I have seen was 4 months ago at DJ's Pet Shop in Woodstock, Ontario Canada. 1 was 32 " the other was 30". They were about 12 years old. They were raised in a 500 gal plywood tank. One of your other replies states that they should be kept in a school and he is very right. Also they need a big tank (a few K). My favourite is pangasius sanitswongi the Imperial or Emperor shark. I had a school of 6 which eventually went from my mini mega 15k to my mega 50k+. They were not skittish in the big tanks and very slow growing. reached 36" at 8 years.
I'm happy with my group of irridescent sharks (P. hypophthalmus). They 'only' grow to 40". Here's one of my albino cats.. I have 3 albinos and 9 standards.