over the last few days i have noticed that some newly bought neons have been disappearing, and i have lost 2 swordtails. I tested my water and everything looks normal, then this morning i checked on my discus and noticed they looked like that were laying eggs, on a closer look it would appear they have layed already much to my delight, could this be the cause of the dead and missing fish ? im not sure how aggressive discus are when looking after eggs etc