The only sign that things may not be good was the cloudy water -- it's still cloudy.So, totally agree with Brandon, my first thought was disease bc of the inverts being ok,
But man that’s one harsh wipeout without seeing any signs beforehand…esp when having purchased qt’d fish. Would never have told you myself that you were doing anything wrong at all having followed your steps. Very sorry to hear but I’m sure your next batch of fish will do amazing.