HELP! New koi pond!

DunnosquatJuly 2, 2013

Hi all,

My husband and I just built a backyard koi pond. Its approx 300 gallons, complete with a pump/waterfall and a new filter. After building, we let it sit with the pump running for about 6 weeks. It became very green and filled with algae about a week in. Last week we installed a filter and treated the water with aquasafe to clear the chlorine and a water clarifier. The pH is about 8.We decided we would add fish, so we bought 2 koi, 4 feeder fish and 3 pleccos (algae eaters!). Well, since putting the fish in, we haven't seen them again. They haven't appeared to eat and we haven't seen a bit of movement. The water is still very dark and green but I feel like we would have seen SOMETHING. On day 2, one of the pleccos had died. I haven't found anymore "floaters" but have yet to see any fish alive either! The pond has very little shade. We made a couple hiding spots, but I'm wondering if the fish have been found by predators? If they died in the water, wouldn't they have floated up? Is it possible they are alive and well, but we just can't see them? They haven't come up for pellets, how long can they go without eating them? Besides adding shade, plants, and a filter- how else can we remedy the dark water? Is the water darkness bad for the fish? We added the fish 3 days ago- how do I know if they are still in there?

So many questions! HELP!

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First off you only need to de-chlorinate the water when you add new water. If the water has been in the pond for 6 weeks the chlorine has long since dissipated. The green water is just unsightly to you and not harmful to the fish. Pleco's won't do a thing to clear green water. They graze on the algae that grows on the surface of the pond liner and other things that are in the pond. The green water is caused by single cell free floating algae. It's normally caused by water rich in nitrogen. You can help control single cell algae by putting plants in your pond to use up the nitrogen. You can also add some shade to help. Algae will thrive in bright light. As for your fish, I'd say don't fret too much. Fish will often hide for several days or more when moved to a new environment. If you are putting food into the pond and it's not being eaten make sure you remove it. Not doing so will contribute to the algae problem. Just visit the pond frequently and maybe just sit around for awhile. When the fish understand you are not going to harm them they will start coming up to visit with you. Oh and I forgot to mention that a UV light is often used to control free algae. You can get one from a pond store or online. Kinda pricey but worth it when you have algae issues.

You have a very nice pond. I'm sure you will enjoy it once gets balanced

    Bookmark   July 2, 2013 at 11:02PM
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So helpful! Thank you!

    Bookmark   July 2, 2013 at 11:21PM
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rsingley(z6a NJ)

Before investing lots more time and money, try to have some patience. Joe(I assume) made a very good point that the algae will feed off the excess nutrients and other plants can help use some of those excess nutrients reducing the food for the suspended green algae.

During the warmer months fast growers like water hyacinth, water lettuce, parrots feather, etc. are very effective. For those of us in the colder climates an early grower like marsh marigold is very helpful since it sprouts from it's winter dormancy before most others and before the green algae.

Prior to planting marsh marigold I used water hyacinth to assist with the algae blooms. Now the marsh marigold handles it without fail.

New ponds always go through the "green" phase. Before you invest lots of money on overpriced filters, UV lights that require constant electric, etc. be patient and let the pond settle in for a few months. After that you should try to find the source of the excess nutrients and address that problem.

It's also likely the same issue will arise next spring, and each thereafter until you have resolved the source.

Good luck.

    Bookmark   July 3, 2013 at 5:38AM
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