Its a Pangasious of some kind - they are a monster of a fish growing between 4 and 6 foot long, that looks like quite a sizable fish at the moment but its going to get bigger.
Here is some info
http/www.planetcatfish.com/catelog/species.php?species_id=268
If you have been offered this fish I would avoid it, if you have been sold it I would try to find a suitable home for it unless you have the means of a huge huge tank.
if this is in your tank .... Oh dear... as stated above these are a monster of a fish! try to rehome if possible or take it back to the store (if bought from a store) and demand a refund!
Beautiful fish, but as stated above... a monster fish! What size tank do you have? If I remember right, these fish also like to be kept in groups. I see these for sale all the time at 3"-5". They definately are not for most home aquariums. Welcome to the forum.
hi there its in a 4 foot tank atm hes about 10 inches been told by local aquarium shop that there poisonous if there top fin gets you? so u have to go to hospital n tell them what fish it is etc...is this true?
Looks like a Pangasius sanitwongsei...walk away, if you have it already then rehome,unless you have a absolutely huge tank in back up..
You looking at one of the biggest fish in captivity, wish fish shops would stop selling these absolute woppers