Please help, my fish are dying?!

So a few weeks ago, my fish came down with what I was positive was ick. I treated them for it and it seemed to be gone. But about a week later it was back and the next day my flame angel died followed by all but four of my fish. My male clownfish is already not gonna make it even if I do find out what it is and treat it. I'm thinking possibly still ick, marine velvet, oodinium, or maybe even brooknella though I'm not sure how often other fish get that. Any help is greatly appreciated. Let me know if you need more info.