OK, I want to tell you this, my friend: I started my 55gal tank with 28 juvies. I lost 7 of them during the first 6 weeks; no losses since then on the last 4 months. So don't get freaked, but of course, keep an eye on them.
About the scratching, was there in the tank any sudden drop in temperature? What's the water temp right now? No signs of ich or fin damage in any fish?