First of all I would like to say that converting a banded cat shark is probably a fools errand. Maybe if you left the water at around 1.005 and put lots of Calcium chloride in the water they might live...
There are several shark pups which can be born into to low salinity conditions, and may for a short period, spend their time in those waters- however, this is never an area of which they would survive for life. This is because their biological makeup, requiring a marine environment. I can post a novel on that if its wanted, lol, but for now I will keep it simple. There is no way someone could successfully "Convert" a marine animal to freshwater by simply putting this animal in FW conditions - all he is doing at this point is buying his time and the sharks, because it will not fare well as time go on, this animal will not last long.
but the big picture here is the gold fish.Notice how they are swimming? This is a salt water tank that has a few goldfish dumped it for effect.
I would love to agree, trust me I would, but at this point - especially only having this particular clip to look at, it seems more likely that the water truly is freshwater, or at best brackish. The Goldfish in there - who actually, look to be Ryukin Goldfish, could not tolerate higher levels of salinity, and in order to tolerate lower ones, would need to be acclimated slowly, and that would still be a 50/50, but they swim like that naturally. I mean sure the mollies are in there and they can be versatile if acclimated appropriately, but what Saltwater Fish are you seeing in there?? I saw one flash across the screen which was a blue/light green color and thought at first it might have been a Chromis, but then again - it could have also been an Opaline Gourami, I didn't pay too much attention and only saw it like once for .2 seconds. Let me know where you are seeing these other fish.
My BS meter is pegged out on this one.
