I purchased a Royal Gramma Basset from my LFS and it went MIA a few weeks ago. Within 2 weeks my 2 clownfish contracted and died of what I believe was Marine Velvet. My hawkfish is still holding strong and showing no symptoms. I started treating the tank with seachem Paraguard. How long should I streat the tank? How long should I wait to get new fish? 40 gallong breeder currently fish only.