Hello everybody;
I moved to Japan 3 weeks ago and just 2 weeks into my move, I receive an urgent message from my family that the fish are dying and so I'm now back home already...
The cause of death was simple; chloramine poisoning due to not adding dechlorinator to the tap water...
Upon my arrival on Friday, there were 3 Koi dead, with another one and a tiny old Goldfish following shortly after...
The survivors that were all hand-tame, were terrified when I approached the pond.
The pond was foaming up so I did a 70% water change to try to clear it up. Since the tap water contains 2ppm of ammonia to begin with, I currently have 2ppm of ammonia still in the pond due to the die-off of the beneficial bacteria. The ammonia levels haven't gone down but today I noticed some nitrites accumulating...so that must mean there's still a small colony of bacteria trying to do their job..? The filter smells bad and so does the water a little bit.
The veining on most of the fish seems to have cleared up and they are now mostly active when I approach the pond. However when I'm taking a sneak-peek, I see that they are mostly inactive with some clamping fins, laying on the bottom...Oh there's one that has completely isolated itself from the herd.
I noticed a Platinum Ogon that really concerns me with a notched nose and eyes that are clearly sunken in...I know that these are symptoms of both KHV & Costia. There are a few fish with a notched nose but this fish has sunken eyes to go with it. And what's with all the wrinkles on it's forehead?
Can chloramine poisoning cause this? I really don't think it's Costia since the water temperature is in the 50's and I just treated the herd in a heated QT right before I left for Japan. Or can Costia multiply and cause these symptoms even at cold temperatures in a matter of a few days?
I'd really like to shotgun treat the entire pond, which I've always had no problems performing, but this time I think it will send the fish over the edge...
...Anyways what could I do with the survivors? With the water parameters being off after they've had their gills badly burnt, I think there will be more casualties in the next few weeks.
I could salt the pond to help with the breathing, but I read that salt can cause cold water to become even colder...and I also use metal hose clamps and a submersible pump and don't want them to rust.
Another thing I could do is to move the fish & filter to a heated indoor stock tank to speed up the cycling process...but I thought I read somewhere that warm temperatures can make the effects of (the same level of) ammonia & nitrites deadlier than in colder water.
I'm at quite a dilemma...I wish I can board them somewhere until at least the filter cycles. I turned off the UV and added Tetra SafeStart Plus today.