paroon shark scientific name is pangasius sanitwongesi. You should ask your LFS if they can get them from distributors. Seems lately they are pretty hard to get. HOWEVER if you look at the buy/sell there are some people wanting to give theirs away
Ive heard they get up to 9feet in the water and it would take a very big tank and a very dedicated owner to get that big
but i think in home aquaria the could maybe get to five if they have the room and clean water