Swai sold in the U.S. is typically the same iridescent shark we buy in the aquarium stores, or one of its close relatives.
It should be okay as a fish in general, but when you're dealing with fish farmed overseas (specifically China) you're not dealing with an FDA certified product. It used to be that the FDA would send food back that didn't meet their standards....but then China "politely" reminded our government that we owe them a ton of money. So now our imported seafood just has to meet the exporting country's standards.
In short, it should be fine for your fish as long as they find it palatable. But take it from me, (a totally biased fish-farmer) you should look into buying stuff farmed in America. You're not only doing yourself a favor in terms of possible antibiotics and contaminants, but these "river-farmed fish" are also attributed to polluted water bodies overseas. It's not like they employ recirculating aquaculture systems, they just throw a bunch of "swai", chemicals, and fish food in the rivers.