I have a ten gallon planted tank that has been up and running for several months. It was cycled well before the addition of fish. There is one Anubias, a hand full of Java Ferns, some Hornwort and I will be adding some Christmas moss shortly. I'm using a LED hood with a compact fluorescent to add extra light. I'm running a homemade Co2 system, a HOB filter and bubbler at night.
My water looks good, no ammonia, no Nitrites, and very low Nitrates. PH is right at 6.4. I do weekly water changes of 15% and swirl the foam prefilter in the removed tank water to clean it off. My plants are growing nicely and it seams that things were going great until last week.
I had seven White Cloud Minnows and six Ghost Shrimp. One fish died with no warning two weeks ago and another developed fin rot. I did a 50% water change and removed the fish with fin rot to a hospital tank. He died within 24 hours. About a week later I noticed that I had one fish that seemed to be having trouble keeping her balance. She then started swimming oddly almost like she had broken her back but hadn't been physically injured in any way that I could see. I had removed all the water from the hospital tank so I set it back up and put her in. I tried feeding her a pea and she seems to be doing better but is still very lethargic. Three days after I moved her I noticed the youngest female in the tank doing the same thing so she was removed to the hospital tank as well. Now it looks like my last female is having the same problem.
I don't want to dose them with antibiotics and kill all the bacteria in my tank if I don't have to but I also can't find any illness that really matches the symptoms I'm seeing.
Any thoughts or suggestions would be appreciated. I hate to loose more fish and I'm worried that I'm going to have to tear the tank down all the way and destroy the plants.