the size and stocking density of your pond - about 1100 gallons, 25 sm-med gold fish, 5 small koi
* the type of filtration you have -- bio filter only, lots of pond lilies... too many, but the water stays clear and I get no algae blooms.
* your maintenance routine, 20% change out every few weeks. It gets hot and dry here and we get a lot of evap so I'm constantly adding water as well.
* the last time you performed maintenance. This past weekend.
* They also need to your water parameters, including the temperature. - i don't have them but my son reads the strips as I'm color blind and can't figure it out. The values have been fine except for hardness and alkalinity, we have very hard water here. In the last 13 years, I've never had water problems.
* The last time you added a new fish. -- added several fish in May when the pond began to warm.
*** My son unintentionally (well, it was intentionally but I don't think he realized what might happen) added a couple of 10 cent feeder goldfish that were for our turtle (kept in a tank). He thought the feeders looked "cool" and wanted to keep them. ***
About two weeks ago I started noticing that one of my best koi was hanging out near the waterfall water return. I thought I might be having oxygen problems though it's never been an issue in past years. I added a small bubbler to improve oxygen. I didn't see any physical issues with the fish.
He continued his odd behavior. When I'd go out in the morning to feed I'd see him up near the water return just hanging out. Very shallow area but surrounded by pond plants.
A few days later I noticed more fish joining him. As many as a dozen.
I did not notice any other odd behavior though that fish quit eating.
Then I started to find dead gold fish that had previously been quite healthy and active.
First one, then two more.
I started searching your forums and began some treatments including salt and a pond medicine from Petsmart, I believe it's called DesaFin.
It didn't seem to help at all.
More fish died. I think I'm at 8 or 9 today. I just fished out one of my hardiest koi. I have a picture
Link to larger: https://lh3.googleusercontent.com/-q...618_203327.jpg
this guy seemed fine a several days ago. He was actively feeding and socializing with the other fish and would come to the side of the pond for feeding. Then, maybe 4 days ago, he started doing the 'hanging around the waterfall return' like the other koi that died.
Today, he was floating sidewise when I took him out. He was still responding to stimuli when I took the photo, his eyes would move but his mouth was locked closed and he looks rather horrible.
I talked to a local pond guy who suggested I ramp up the salt levels to 6%. I didn't see anyone here recommend that number so I tried to be a little more conservative and it should be 3-4%, but I have no salinity testing apparatus and can't be sure.
Another thing I added a few weeks ago were floating plants, one water hyacinth and one water lettuce (both of which have started reproducing).
I have a couple other photos of other dead fish.
These were number 3 and 4, although the first koi to die.
Link to larger: https://lh3.googleusercontent.com/-i...o/IMG_6936.JPG
Here is a link to another fish, a goldfish, that died yesterday.
https://lh4.googleusercontent.com/-Q...617_193026.jpg
So, Monday, I did a 25% water change and added 2 pounds of salt, pulled a bunch of plants out of the water in case the salinity level is too high.
The remaining fish are crazy skittish over the last 2 days. They will come out to eat but dart up to the surface very fast and hide again.
I don't currently see any exhibiting signs that these other did before they died.
Hopefully I'm not rambling too much.
Thanks.