Around March, "Fred" our first and largest goldfish became ill (head down, fin up), and I proceeded to research and find out what to do, and what to buy to "fix" him (I did not want to give up on him). Well, nothing I tried worked and he hung on for about 2 more months. (I now think he ate a pebble during a warm spell and couldn't digest it) Anyway, all during this time the water quality got worse, the other fish were not eating very much, and I kept trying clarifying chemicals, water changes, bacteria, etc., but even the string algae was not growing like it usually does in the spring. Plants were not growing, water was pea soup, couldn't see any of the other 6 fish to check their condition.....things were not good. I have never had a serious problem like this before and didn't know what else to try (other than doing nothing which also didn't work).
I found during my research some info. about the benefits of "Koi Clay", and how it could detoxify the water and fish. Well, I figured after trying just about every chemical additive out there, I might as well try this - the benefits I read about seemed almost too good to be true. But I also knew after adding all these different additives to "fix" Fred and the water, and with the problem getting any plants to grow, it was time to de-toxify! The clay arrived in the mail and I immediately gave a big dose to the pond water and fed some to the fish by adding some to the fish food, and prayed that something would improve.
Wow! Exactly one week later, the "carpet" algae on the sides has appeared, the water is crystal clear, the fish are happy and hungry, and the plants are starting to grow like crazy! This stuff was the solution I had sought for so long!
I will now add some to the fish food by dusting it on some moistened pellets and add some to the water each week. I'm also considering taking a bath with it for myself! I just cannot believe the difference it has made in my small pond - it really seems like a miracle cure!
I haven't read any other success stories about "koi clay" like mine but hope my experience might help someone else who can't find a cure for their pond or fish. I just wish I knew about "koi clay" before I lost Fred - this stuff might have helped him survive! BTW - many thanks to all the contributors for all the great info. on this forum - I learned about "koi clay" from a post here.