Pretty much what I'm doing now.
Starting from the beginning...
August 14-27 i was out of state and asked my dad to feed my fish for that time. I did 100% water change before I left and did a 100% water change when I got home. Unfortunately one of my girls contracted dropsy. Nox died in the first week of September.
This caused my girls to re establish the pack placement and Kasey was picked on to the point of loosing a pectoral and ventral fin. So I moved her to a 1.5 gal. her color brightened up and she ate... started treating her for the fin loose with melafix. Followed the directions but she stopped eating and two weeks after Nox, Kasey died. I don't know from what because she wasn't bloated, no pine coning, no white spots, no yellow spots, no white fuzz... etc. She was just pale and stress stripped when I found her.
And a week later Coral died. I have been back on my normal water changing cycle, 25-50% water changes. I move around everything to make sure I get all the waste... once a week. Everyone was acting normal, no signs of illness. Still eating like little piggies... but anyways I went and did the girls water change, and then later that night fed them. Everything was fine. I went to work and when I came home, Coral was dead. Her fins were shredded, when they were in perfect condition less then 24 hours ago.
I don't know what I'm doing wrong. I have a ten gal tank. 78 degrees, I use tetra aqua safe water conditioner with bio extracts. I added some api aquarium salt because I had put a new fish in when I moved Kasey to the 1.5 gal. I do 25-50% water changes weekly and after Nox got sick I did a total tank cleaning. Cleaned the tank with vinegar and hot water. Then cleaned the gravel, plants and pots with just hot water. I changed the carbon in the filter. I just don't know. Everyone has a bit of fin loss due to establishing the alpha of the tank. No one is bloated, or lethargic. I'm worried because Coral died without warning, so now I think I could have a problem. I'm treating with melafix for the fin damage and all the girls have regrowth. There are 5 girls in there, and I'm not going to get another because I don't want to introduce another girl if I have a parasite or fungus.
Hoping for some light to be shed on this situation. I use a multi strip test and my chlorine is none, nitrate is zero, ph is good, my water is a little hard ( I have an aquatic plant in a vase I use as a control. ) I know strips are not as reliable as liquid drop tests but its what fits my budget.