Greenwater HELP!! Koi pond Help

  1. C

    CLam Valued Member Member

    Having an issue with greenwater in an outdoor pond, last week it was crystal, yesterday, it was opaque. I don't actually know exactly how big the pond is, but I'd estimate it as maybe 6'x10' and 4 to 5 feet deep. It's not mine, but my grandfather's, except he's really been touch and go the past year, and hasn't been able to attend to the fish lately.

    Any information on how to handle greenwater on this scale would be greatly appreciated. I'll probably be going up to my grandparents' later this week to help my aunties figure this out. My grandfather really is the only fishkeeping-literate person at the house at the moment, but he's not been up to talking so much.
  2. gremlin

    gremlin Well Known Member Member

    I had that issue in my goldfish pond. I hated it. The water was green, I couldn't see more than an inch in to it, filters didn't touch it, netting it didn't work, not even cheesecloth. Then I got a new filter - with a UV light. No more green water. The UV kills the "green" and makes it clump together so the filter can actually remove it. Since I got the UV filter, I've not had green water at all. My sister is the same way with her pond. She added a UV filter - no more green. I don't know what type of filter is currently on your Grandpa's pond, but it shouldn't be too difficult to add some type of UV on it.
  3. millca

    millca Valued Member Member

    Some goldfish and koi breeders desire the green water and work hard to cultivate it as it has huge benefits for the fish. So don't panic. Search for "green water goldfish" and you'll find articles about it.
  4. Coradee

    Coradee Moderator Moderator Member

    I always used barley straw in nets when I had a pond, it's used a lot here to keep algae growth down in ponds
  5. OP

    CLam Valued Member Member

    Too late :(

    Aunties got there first. I found out they did a huge water change, and in the next few days, six fish jumped out. On my next visit, I fished out two dead koi.