I think you are going to struggle to even support a jeuvie on that system for more than 6 months. The fish have huge requirements as far as swimming space goes. My baby arowana is in a 55 quarantine and as the same sorta requirements. The fish is only 5 inches long but the 55gallon(48 inches long) is way to small for a healthy swimming pattern, look at the ratio 5-48 way better than you'd have with a 2 ft to 8 ft and sharks swim faster. Yeah a 1-2 ft fish could probably make it in your tank for a month but the moment it grows past 2 ft your tank would be a major inhibitor. Sharks, more specifically the ones you are looking at can't stop swimming and that tank will basically have it turning in tight circles all day. If you've ever kept a fish like a zebra danio or rainbow in a hexagon tank you can see a small amount of what will happen to your fish the constant tight turning would really inhibit its development. Before the fish looks like its outgrown the tank its back will arch to the one side it turns most often. Yes you can sight the fact that many on these forums have fish in tanks to small for them and people celebrate them, arowana are definitely among those fish more often kept in the wrong conditions than the right but I would plead reconsider and go with a cat shark it will fair better in your tank and you will be happier for it.