saltwater fish are easy to keep, with no coral or inverts. My guess is that they "Hired" a tank cleaning service that actually keeps their fish alive. I'd remove half of that rock so those fish could move around a bit. If they truely want "Monster" fish I think they need to get FW fish..... and if they have that much money, how about do a 3,000Gal build for a Gigas.. that thats a kick as Fish only tank. I could have built a 3,000 gallon tank for less than I'm sure they paid for that 300.... these guys don't know fish.