I have a 20 Long, very well planted tank. Started with 12 bettas, down to 6 with a couple being re homed. I have lost 3 in about 2 weeks. My water levels are decent, we have a high PH where I live, but most of my girls were bred here and have been acclimated to it. My ammonia and nitrites were both under .225 ppm, but my nitrates were in the .40 range for a when I worked the day I normally clean their tank and had to put it off, but I've changed their water since and I normally do weekly 30% changes and I always use water conditioner. Their tank stays around 82 depending on how hot it gets here, but they've always seemed to enjoy the warmer temperatures. All of a sudden my happy little sorority is falling apart. I was being vigilant and watching them, I am treating one with dropsy now in a separate tank, but the three others who died were just getting a little slow and then the next day they were floating. They weren't incredibly bloated, but their stomachs were slightly distended and grayish. Otherwise they seemed mostly healthy, they're fins look great, they were all growing into their color and really bright, no white spots, no bumps or contusions. It was just such a quick transformation, and I thought if I did a few extra small water changes it might help. Anyway, now there are 2 more who seem to be getting lethargic and I am now recognizing the signs early enough to possibly treat whatever it is. Is it my water quality? It's been so healthy and clean especially with all the plants getting larger. They have all been growing and their colors were looking really great! I've been reading so much and trying to decide what to do. I am suspicious of parasites or possibly bacterial infection? The one with dropsy had been in my kuhli loach tank for a while after she had been bullied too much, but once she healed I put her back after totally cleaning everything and rearranging it. That was about 2 weeks ago. I'm trying to think of as many details as possible that mthe gut effect it. If you have questions, let me know! Please give me suggestions or any bit of information that may help! Update the one with dropsy died and another is showing signs of being sick. I don't understand because the water seems better than it has been. I cycled it for 4 weeks before adding them even after using an old filter. What is happening? I feel so terrible and I have put so much effort and care into these ladies all for some unknown thing to take them out. It's heartbreaking. Please help.