2 days ago one of my neons died suddenly out of no where. Swimming around normally and happily the night before. I woke up the next morning to find him dead so I did a 30% water change. That day the neon died I saw my black lace angel in the corner not moving. But he was never really social so I didnt think anything of it. The next morning he was dead floating around my tank. I took him out and wanted to test my water but couldnt because my dad had moved it and he was a away on a trip. Next morning (today) I find my zebra / blue angel going around in circles frantically. I put him in my qt tank, and life left him in a couple of minutes. I'm doing a 50% water change now. Oh and my zebra was swimming around happily with his other angel bud yesterday. What I did notice was that the nose was red. So what's wrong with my tank? I don't want all my fish to die. Honestly. I can't keep doing this. Its hard for me to see my fish die and every time I have a wave, it makes me scared and not want to take care of fish anymore.