skullcraca chill, dmopar means no harm. he's been around a long while and his comment is more like "u should grow out the aro a tad til he's more beefier, then toss him back with them at a bulkier/older stage in life".
he was just quick to get his msg out, and it came off wrong. but in my opinion, as an arowana keeper and not at small tank small fish level, arowanas at that size are very very delicate and sometimes even die off without tankmates at that size. yours is with heavy feeders and fish that are not afraid to throw some bites, that a silver arowana at that size wouldn't be able to take much of.
in the end there your fish. im stubborn at times too, or maybe dont have a tank to move a fish too, and sometimes i jus try anyway. ur choice buddy.