Koi Not Eating

[ScottWinn]

Hi all,

I'm new to these forums and new to koi. I purchased a home and inherited a beautiful koi pond. According to the former owner it's roughly 2,500 gallons (this could be wrong) and I estimate there are 35-40 fish in there. Over the first month I made sure both filters are cleaned every 2-3 days so oxygen levels should be good. I also use the net every day and sweep leaves and flowers off the top. I fed them Tetra Pond Spring and Fall diet (blue package) for the first month but now water temps have been hovering over 60 degrees so I switched to the Tetra Pond Sticks (green package). They stopped eating immediately. I reordered the other food and they won't eat that as well.

I live right next to Wetlands and there are definitely Blue Heron in the area. A neighbor told me that the Heron were able to get in there in years past and take fish out of there. I've have seen Blue Heron in my yard twice in the last week and I do have fishing line up around the pond and it seems like they haven't been able to get to the fish. I mention this because I thought it's possible they're being affected by a predator

I have a water test kit on the way because maybe ammonia levels are off or something is not right but any ideas why they stopped eating?

Thanks!
Scott

 

[Jhn]

That is a lot of fish in your size pond unless they are all small goldfish.... but I assume not since your thread title is koi not eating. What type of filter/pump are you running? How big are your fish? Post water parameters numbers once you get your test kit....

I will say whatever your water parameters read if those fish are all koi, they are going to overwhelm your biofilter at some point over the next few years as they get bigger. Ideally, you would keep roughly 3-4 koi in a pond your size.

Their current behavior and the fact that all of the fish stopped eating at once, would lead me to believe a predator was around, so now they are skittish to come to the surface to feed. If they are hanging deeper in the pond and not coming up or coming up abit then darting back down before getting to the food then that is typical behavior after a predator of some sort has been at the pond. Just an FYI herons will figure out the fish line thing eventually, unless you put so many up that you can’t get through it.

 

[poconojoe]

I also think it's a good chance they are acting that way from being spooked by a predator of some sort.
Give it time.

 

[j.w]

@ScottWinn

 

[ScottWinn]

Thanks guys I appreciate it! They haven’t eaten in well over a week so I’m getting a little concerned. But we have spotted herons out in our backyard about 15 yards off the pond twice. That’s what I’m aware of it could have been more times.

I count close to 40 fish and yes, they are all Koi to my knowledge. The guy left me no info but what to feed them. One of them is close to 16 to 18 inches. Here’s a few pics and I use two of these submersible pumps.

From these photos you can see the fishing line I put up and the part - which is the grassy part of my yard - from which the herons approach. I have two fishing lines there. But until I see them in action I don’t know what they’re capable of regarding sidestepping those lines.

I do have some green wire fencing that’s used for gardening. I can seal off that spot that I think they’re coming in from. Does anything else work for herons?

 

[Tula]

We erected a "hoop" over our pond with electrical conduit we spray painted black. We use rebar to secure the ends in the ground. We then spread a wide weave fishing net over the hoop that we bought from Memphis Net.

 

[Lisak1]

It's hard to tell from the picture, but it does appear that some of those fish may be goldfish. In any case that's a LOT of fish for 2500 gallons. A subject for another post...

As for the fishing line - it may work, but then again many a heron has defeated that particular strategy. The only 100% foolproof method is to net the pond. Your water is murky, but that's not all bad either when you're trying to keep your fish safe - they're a bit harder for the bird to see.

As for the fish not eating - that is one very telling sign that they have been spooked by a predator. Don't worry too much about it - they can find things in the pond to eat so they won't starve in a few days or even weeks time.

 

[mgmine]

As JHN pointed out 3 to 4 fish is all that you should have in a pond that size. A pond should be peaceful to watch. I will say this since you are new to ponds. Don't believe everything you read. For example, don't believe that fish need some special fancy food in the spring then a different mix in the summer and another in the fall. I buy one bag of food and that's is what they get. I have never had a fish die due to lack of eating or a lack of testing the water. When you get your water testing kit do yourself a favor and throw it in a drawer. You're already talking ammonia levels, and that is going to start you down the rabbit hole. When you test the water you will find that those 40+ fish should all be dead. That's what the internet says so it must be true. As I've said many times before, fish don't read so they don't know that they can't live in the water that they live in. Keep them out of schools, don't let them read and they will live to a ripe old age. Try to adjust the water to what the internet or the on line pond stores tell you it should be and the fish will not be any better off. You however will be poorer.

 

[ScottWinn]

It's hard to tell from the picture, but it does appear that some of those fish may be goldfish. In any case that's a LOT of fish for 2500 gallons. A subject for another post...

As for the fishing line - it may work, but then again many a heron has defeated that particular strategy. The only 100% foolproof method is to net the pond. Your water is murky, but that's not all bad either when you're trying to keep your fish safe - they're a bit harder for the bird to see.

As for the fish not eating - that is one very telling sign that they have been spooked by a predator. Don't worry too much about it - they can find things in the pond to eat so they won't starve in a few days or even weeks time.

I’m a teacher and I’m off for the summer starting next week and I’m hoping I can outthink it. I just need to observe it and how it moves and acts. There are wetlands right behind our house so they fly over our property all the time. A net seems like a good option but probably a pain in the butt to clean.

I tried to get that water clear but probably because of all the fish in it maybe it’s just not possible.

As JHN pointed out 3 to 4 fish is all that you should have in a pond that size. A pond should be peaceful to watch. I will say this since you are new to ponds. Don't believe everything you read. For example, don't believe that fish need some special fancy food in the spring then a different mix in the summer and another in the fall. I buy one bag of food and that's is what they get. I have never had a fish die due to lack of eating or a lack of testing the water. When you get your water testing kit do yourself a favor and throw it in a drawer. You're already talking ammonia levels, and that is going to start you down the rabbit hole. When you test the water you will find that those 40+ fish should all be dead. That's what the internet says so it must be true. As I've said many times before, fish don't read so they don't know that they can't live in the water that they live in. Keep them out of schools, don't let them read and they will live to a ripe old age. Try to adjust the water to what the internet or the on line pond stores tell you it should be and the fish will not be any better off. You however will be poorer.

That’s an interesting take. I have not tested the water yet as I wasn’t overly concerned about it and know they are hearty species. I was only introducing that as part of the troubleshooting as to why they’re not eating. I suspect with all the pooping ammonia levels are high.

Also yes I agree with you I did not sign up for spending $1000 upkeeping a pond this year. It came with the purchase of my home and I’m thankful for that because it’s such a beautiful future and I do have a lot of experience with aquarium fish so not a total noob. I’m a bit house-poor at the moment until both my wife and I go back to full-time this fall so not likely I’ll be spending a lot of money.

Thanks for the tips and I don’t want to go into that rabbit hole if I can help it. I have plenty of other things that need my attention and if something is getting to be too much work for me than the enjoyment level goes down. With that said I will take good care of these fish, I just won’t go overboard.

It’s good to know that my fish are getting what they need from the pond itself and I’m not going to over-worry about the food. I’m trying a half a handful a few times a day if they don’t eat it, I scoop it out and try again tomorrow.

 

[ScottWinn]

I’m a teacher and I’m off for the summer starting next week and I’m hoping I can outthink it. I just need to observe it and how it moves and acts. There are wetlands right behind our house so they fly over our property all the time. A net seems like a good option but probably a pain in the butt to clean.

I tried to get that water clear but probably because of all the fish in it maybe it’s just not possible.



That’s an interesting take. I have not tested the water yet as I wasn’t overly concerned about it and know they are hearty species. I was only introducing that as part of the troubleshooting as to why they’re not eating. I suspect with all the pooping ammonia levels are high.

Also yes I agree with you I did not sign up for spending $1000 upkeeping a pond this year. It came with the purchase of my home and I’m thankful for that because it’s such a beautiful feature and I do have a lot of experience with aquarium fish so not a total noob. I’m a bit house-poor at the moment until both my wife and I go back to full-time this fall so not likely I’ll be spending a lot of money.

Thanks for the tips and I don’t want to go into that rabbit hole if I can help it. I have plenty of other things that need my attention and if something is getting to be too much work for me than the enjoyment level goes down. With that said I will take good care of these fish, I just won’t go overboard.

It’s good to know that my fish are getting what they need from the pond itself and I’m not going to over-worry about the food. I’m trying a half a handful a few times a day if they don’t eat it, I scoop it out and try again tomorrow.

 

[Jhn]

If you get a wide weave net there is no cleaning necessary, leaves and debris will fall through it. You can even add tall posts or poles in strategic spots and string the netting up like a curtain, then slide it out of the way while you are outside enjoying and close it up when not around to keep predators out.

As for getting your pond to clear as @Lisak1 pointed out the murky water is a good thing if herons are around it makes it harder for them to see the fish. Adding plants, plants and more plants will help greatly with algae/green water control and your water quality. Adding a bog would be even better, in helping with all the above. Keep in mind, like we tell everyone that comes here murky or green water doesn’t equal bad unclean water quality, the fish don’t care what their water looks like just that it is a healthy environment for them to live in.

Also, agree with @mgmine not big on testing my pond water.....as in I never do it. Will add though I have over 30 years experience in keeping fish in aquaria, as well as ponds.
For people new to fish keeping of any type it’s not a bad idea to test your water, but you need to understand what you are looking at, and the cause and effect of the readings..... not chasing certain numbers because that is the ideal, big swings in many water parameters like ph is not good, steady and stable even if it is not perfect is best. Use your fish as a barometer, pay attention to how the swim and act, and you will be able to tell when something is off with out testing anything, and whether it is a predator that caused the behavior change or your water quality declining.

 

[mrsclem]

It sounds like you have had this pond about a year or less. It looks like some of the fish may be goldfish. Testing is not a bad idea since you are new to this. With that number of fish, you want to watch for ammonia. Fish grow every year and reproduce. 30 fish this year can very easily become 60 next year!

 

[brokensword]

I have a couple of cheap trail cams to help me see the movements of deer through my yard; you could do similar to help with your herons. All that said, a net is still the best solution.

 

[ScottWinn]

It sounds like you have had this pond about a year or less. It looks like some of the fish may be goldfish. Testing is not a bad idea since you are new to this. With that number of fish, you want to watch for ammonia. Fish grow every year and reproduce. 30 fish this year can very easily become 60 next year!

I’ve lived in my new house for two months and it was the previous owners. He left me little to no information so I’ve been learning on my own.

Here is my test. I know strips are not the best but everything seems to line up pretty well and water quality doesn’t seem to be too much of an issue unless general hardness is an issue.

Chlorine seems a little high at maybe three. Alkalinity may be a tad low. Carbonates seem like they might be a little high. pH is a bit high at 9.0.

I glued a few CDs together and I’m going to hang those near the tighter entrance to my pond from my lawn. I say tighter entrance because I’m also putting up one of those green wire gardening fences that I have in my shed. If this heron wants to walk in he’s going to have to go through a series of obstacles.

 

[brokensword]

I’ve lived in my new house for two months and it was the previous owners. He left me little to no information so I’ve been learning on my own.

Here is my test. I know strips are not the best but everything seems to line up pretty well and water quality doesn’t seem to be too much of an issue unless general hardness is an issue.

Chlorine seems a little high at maybe three. Alkalinity may be a tad low. Carbonates seem like they might be a little high. pH is a bit high at 9.0.

I glued a few CDs together and I’m going to hang those near the tighter entrance to my pond from my lawn. I say tighter entrance because I’m also putting up one of those green wire gardening fences that I have in my shed. If this heron wants to walk in he’s going to have to go through a series of obstacles.

Chlorine should be zero. Test strips are notoriously inaccurate. Hardness does matter. pH should be stable, though 9 is a tad high. A more accurate test might give you lower results in this case. With such a high pH, having a low alkalinity seems oxymoronic.

A heron is a very patient and persistent predator.