Sad Sad day...

So it happened. 10 months into the tank all was good. Stuff was happy. Fish were fat and eating, swimming around all playful then BAM! My gramma dies suddenly. Then BAM! my Anthias goes down. Within 24 hrs. Neither were showing any signs except day of passing away. Hiding, looking clearly stressed. Now......after that I could see my brown tang (Buck) my daughter named him. He was rubbing on rock and sand and swimming into my power head current. Clearly he was agitated and was looking for relief. About a day later I could see the white spots. These were more of a dust like his skin was flaking off. That when I realized I might have velvet. Buck parished followed day later by one of my clowns. That?s 4 fish in about 6 days. I still have the male clown, fox face and blue cheek Gob. Foxface is not looking hot and seems very stressed. He still parks in front of cleaner shrimp thou to get hooked up with a cleaning. Eating a bit. He?s a fatty thou so won?t starve right away I feel. The clown and goby are both eating like nothing is happening to them. But both spooked as I?m sure they can feel the swing in tank and missing some pals. Wife and I a crushed