[geekdafied]

Im willing to bet the phyto is what caused an outbreak Amyloodinium. I had a similar situation last year or the year before with cyclopeeze. It was a total loss as a result. You overfed phyto like I did with cyclopeeze thus producing a lot of excess micro food that fed the dinoflagelettes. The dino's (Amyloodinium) went after your fish once the tank was overrun with them. Thats what happened to me.