Koi attacking plants

[JohnM2001]

Hey all, I'm new here. Have had my koi pond for 8 years, and have done well, with 12 fish now, some over a foot, and haven't lost any for a few years.

My issue now is plants. Last year, I would find my water lilies uprooted, and floating in the pond. I thought I was potting them incorrectly. The the other day, I just put in my first water lily of this season, in it's original pot from the nursery. I put small rocks on the top to keep it weighed down . The next day, I noticed that the pot had not moved, but all the small rocks were gone from the top of the pot, I replaced them. Next day, the plant was floating on the surface, with a mess of soil in the water, and scattered rocks. I cleaned the pond and filter, got the water clear again. I repotted the water lily in the same container in the special pond soil I have (which is like fine gravel), again placed the rocks on top, but this time I loosely wrapped the top half of the pot with some mesh fabric, with the stems poking through, secured by an elastic around the pot. Much to my surprise, it was the same thing today: everything ripped apart, plant tuber floating on the surface.

I think this must be a playtime game for the koi, or they are upset by these plants. They don't bother too much with the floating water hyacinths, but sometimes play with them too. How can I secure my water lily to prevent them trashing every day? I never had this problem in the past, always having a gorgeous water lily display, and want to achieve that again.
Thank you!
John

 

[j.w]

@JohnM2001
I don't have koi but I've heard about their antic's! Some people use floating islands w/screen on the bottom. Others use net bags hanging over the side into the pond. You have to keep the plants out of their reach as it's the only way! I'm sure others here will let you know more about this subject soon. Good luck....you will need it

 

[BKHpondcritters]

I was pretty much in that same boat last year. 7 years of successful lilies planted directly in the gravel on the bottom of this pond when my ever growing koi started doing enough damage to them that something had to change.

What we did this year was to plant all the lilies in large dishpans filled with a mixture of clay kitty liter & aquatic planting soil, then covered the top of the pan with welded wire fencing pieces so the fish can't get to the soil/tubers but the stems can grow right through & up. We made very sure to bend the ends under & file all rough/sharp edges so the fish wouldn't hurt themselves if they brushed past. So far, so good...

 

[WaterGardener]

I do a similar thing as BKHpondcritters to keep my goldfish out of the water lilies. I plant them and cover the pots with plastic mesh from one of the big box stores. I drill holes in the top edges of the lily pots or pans and zip tie the mesh to the pans. It works well for me.

 

[Tula]

I do a similar thing as BKHpondcritters to keep my goldfish out of the water lilies. I plant them and cover the pots with plastic mesh from one of the big box stores. I drill holes in the top edges of the lily pots or pans and zip tie the mesh to the pans. It works well for me.

This is exactly what I do

 

[mrsclem]

Me too!

 

[Lisak1]

You people need to discipline your fish. A simple time out now and again would be useful.

I think this is something that fish either do or they don't - and once they start it's tough to get them to stop. Do you have other rocks and gravel in the pond that they can mess with? Our fish move gravel constantly, but they don't really bother my plants.

 

[BKHpondcritters]

You people need to discipline your fish. A simple time out now and again would be useful.

I think this is something that fish either do or they don't - and once they start it's tough to get them to stop. Do you have other rocks and gravel in the pond that they can mess with? Our fish move gravel constantly, but they don't really bother my plants.

Oh, trust me, I tried to discipline them. Day after day I said "No, no! BAD fish!" But those sassy little buggers just kept on uprooting my lilies! My whole pond bottom is covered in gravel, so they have plenty to "play" with, but... the darn tubers must have kept getting in the way of their fun.

 

[Lisak1]

Well, we can't all be perfect fish parents, I guess.

I was at a local pond store one day and a lady came in absolutely furious that her koi had devoured her expensive tropical water lily. Come to find out, she had gone on vacation and left them to their own devices. They were HUNGRY! The owner sold her another expensive tropical lily and after she left said "she'll be back. Once they get a taste for lilies, they'll never stop!"

 

[JohnM2001]

Thanks all! Well, I didn't have any gravel or material on the bottom of the pond, and heard that they prefer that, so yesterday I covered the bottom of the pond with well rinsed smooth stones 1-2 inches each. They seemed to like it right away, spending much time down there foraging around now. I plan to add some more larger smooth stones, for variety. I think they were bored.

I'll re-pot the lily in a larger weighted pot, and cover the top with a wide mesh plastic screen, so the plant can get through, but the koi can't get in. I have it isolated in a 5 gallon bucket right now. Only other plants are 5 floating water hyacinths, which usually spread to cover 60% of the surface in August here in New England. We end up culling some of the hyacinths later in the summer when they spread too much. If I can again succeed with the 1 protected water lily, I'll add another, and was thinking of just grabbing a native white one from a nearby pond, is that OK to do, using a native species water lily?

My pond isn't too big (see attached pics), probably an 8 foot circle, 3.5 - 4 feet deep, so I'm thinking about 1300 gallons. Waterfall on top. 1200 gph pump, 1600 gph UV filter on top, cleaned every 1-2 weeks, depending on water quality. I started out with 5-6 koi. Then about 5 years ago, had a massive amount of baby koi minnows, probably 100-200. Most all were dark with no color. It took a while to scoop most of them out, leaving only the ones with color. From all this, I now I have 12 koi total, some getting very big, others 6-8 inches. I'm surprised there have not been any more baby fish in the last 5 years, but happy about that. Does 12 healthy size koi sound like too many in a 1300 gallon pond?

 

[JohnM2001]

OK, taking the koi tough love approach with some fencing over the top of the water lily container, with rocks to weigh down the tuber. We'll see if they leave it alone now, or still try to pull the tuber out. I also added a bunch of new smooth rocks on the bottom of the pond, we'll see if those distract them too.

 

[Mmathis]

@JohnM2001 There ya go!

 

[BKHpondcritters]

Looks good. Pretty much what I did & (so far, at least) it's working to keep those koi at bay.

In answer to your question, I'd say that 12 koi in a 1300 gal. pond is pretty much over stocked. I have that many in 3000 - 3500 gals & I'm concerned about my stocking load. You might have to consider re-homing some of the koi if water quality issues become a problem for you.

 

[Lisak1]

It is too many fish, and your pump is probably undersized. The standard advice is to double the gallons of the pond - so 1300 gallon pond you should have a 2500 GPH pump, or larger. Just something to think about, while you figure out who needs to get some lovely koi!

Do you see your fish spawning ever? If so, they are probably eating all the eggs before they can hatch.

 

[mrsclem]

I have 7 large koi and over a dozen 6-15" in 4800 gallons. Running a bog filter as well as 2 other filters! I had planned on removing 5 adults and most of smaller but Covid hit. I have to keep a close eye on water conditions so with 1300 gallons, I would say 2-4 koi. BTW- My adults range in size from 22-36"!