New Pond Owner - Fish Dying

14 years ago

I had a 400 gallon pond installed last august. It has a skimmer box w/netting and brush, waterfall, etc. I'm not sure if it has a filter. I don't think it does. Anyway, I put 2 small koi in it last september, they lasted until november, then disappeared. They were healthy up to that point. I believe a bird got 'em. I've added a fake alligator and blue heron to hopefully remedy the situation.

I did not have any fish in the pond all winter. I did develop a bit of an algae problem during the winter. I got as much of it out of the pond by hand, but I also started adding some microbial algae control liquid. I put 6 fish(3 goldfish and 3 small koi) in the pond about 3 weeks ago. 2 of the goldfish died within about 3 days. I called the Garden Center where I got the fish and asked them if they had any problems with there fish. They said they had some Ick as they neglected to add salt to their tanks. They replaced the 2 fish. They also told me to add salt to my pond to bring it up to about .2. The day I added the salt I noticed another sick fish(Koi). He died a few days later. I had my water tested and found my salt level to be at .26, my ammonia was zero, and was told my nitrites were "a little high". Not sure what they were, but I know now it's .25. Was told the .25 was okay with my salt level, which I just increased to around .3. Things were fine for a couple of weeks, until this past weekend. I now have another sick Koi. I re-checked my Nitrites last night and they were at .25. I thought my salt would counteract the effects of the nitrites, especially since they're not that high. Do you think my fish are dying from nitrite poisoning? PS - I've also been using Nite-out for about 3 weeks. It's supposed to break down the Nitrites.

Is there something else I need to do? BTW, it's a 400 gallon pond, and my fish average about 4-5 inches in length. I've been feeding them daily, but I think I may cut that out for a few days. Any suggestions on what else I can do? Do I need some sort of biological filter in addition to the skimmer box and waterfall thingy?

Sort by:Oldest

Comments (3)

lotuslady_ca
13 years ago
Do you want some plants? You may need some nitrogen from the roots of the plants. I have plenty, just pay postage Kathy
hazydavy58
Original Author
13 years ago
I appreciate the offer, but plants will not survive in my pond. My salt level is at .30% to compensate for my .25 nitrite level. That sick fish died, but it didn't look like nitrite poisoning. It was some sort of injury(on his back) or parasite. My other fish are doing well. Gonna scale back the feeding and keep using Nite-out to try to get the nitrites to zero. I did clean out my filter this weekend, so we'll see what happens.
hazydavy58
Original Author
13 years ago
Not that anyone is listening, but I cleaned out my filter(s) and added more Nite-Out and my Nitrites are finally at zero! Checked my ammonia and that is also at zero. I picked myself up a new very small Koi this weekend. I do have a Koi with an abrasion on it's side. I believe she got it running from the males during spawning activities. The abrasion seems to be getting bigger, but the fish is acting normally. Other fish seem to be nibbling at the wound and I believe that's why it isn't healing. Any suggestions other than taking the fish out and putting it in another tank, which I don't have?