Koi lethargic, white film over one eye and appears to be getting skinny

[kmarcel]

My oldest koi has been acting funny the last several days. It stays by itself in one section of the pond, looks emaciated and has a white film over one eye so that you can hardly detect the black eye itself. This was my largest koi and is the oldest I have, maybe 15+ years. I have also heard occasional jumping, which I know is not a good sign and there has been some occasional flashing with all the fish. I did a Praziquantel treatment yesterday. I saw some flashing a couple hours after that but not since then. The one koi in question has now been swimming a bit more with the rest and is acting a little better. But I think there may be a bacterial infection that needs to be treated in addition to the flukes. All the other fish are acting fine and there are no ulcers on any that I can see.

The water tests are all good.
Ammonia - 0
Nitrates - 0
PH - 7.5 same at night and in the am

There are only 5 koi, with the largest about 14". There were 7 a couple weeks ago but noticed that the two smaller were missing last week. I assume by a Heron as that happened a few years ago. The pond is not large, less than 1,000 gallons, but the load is light. I do frequent/weekly water changes. There is plenty of oxygen as I have two water falls, a stream and four bubblers.

I do not have access to a microscope and whatever I do I would like to treat the pond and not capture the fish and treat individually. I have always had good luck doing that.

My question is can I treat the water for a bacterial infection since I just did a Prazi treatment yesterday? Will that affect the effectiveness of the Prazi treatment? I have been successful treating my pond when I had a fish with ulcers, fin rot, etc., especially since my pond is small.

Do you think this fish is merely dying of old age? I have read that domestic koi don't live as long and I know it's over 15 years, just not sure how much over.

Karen

 

[Tula]

I don't know the answer to your question, maybe check Koiphen.com and read their files on illness. I know that some treatments cannot be combined with salt or are ineffective depending on temperature.

You mentioned flukes, how did you make that diagnosis? What makes you suspect a bacterial infection? Is it possible the white film over it's eye is fungus?

 

[Lisak1]

I too am curious how you came to the conclusion that your fish had flukes. Not questioning your diagnosis - just wondering.

 

[kmarcel]

Honestly, just taking a guess. I used Prazi before and it cleared up issues of jumping and flashing so thought since I read recommendations to treat with Praziquantel every spring or summer a preventative measure, that I would do so.

I did have an issue with flukes a couple years ago, diagnosed via microscope from person in koi club, which since has been disbanded.

 

[Ray G]

Jumping and flashing are indicators of external parasites. So I agree with the prazi use in this case as the fish are probably seriously distressed. The fish are not old for Koi.
So the question about bacterial infection is a good one. Often parasites lead to bacterial infections due to the lesions caused by the parasites. So you could be right. loss of weight could be internal parasites. I would monitor carefully after the prazi treatment and not add anything else yet. The prazi could fix everything apart from the milky eye. Wait and see I would suggest at this stage as the prazi possibly has already fixed the main problem.

 

[Lisak1]

Honestly, just taking a guess.

Gotcha. We're dealing with a similarly perplexing issue in our pond right now and just wondered how you had come to that conclusion. I agree with @Ray G - I wouldn't treat for bacterial infection unless you see signs that it's a problem. And I know you said you like to treat the whole pond, but that's kind of like treating your whole family for a medical problem that only one of you has. I don't like trying to catch my fish either - it seems so stressful for them - so I get it. If the fish is showing signs that he's improving, I'd leave it alone for now and just observe.

A little unsolicited information: I know you said your fish load is light, but in a less than 1000 gallon pond, 5 koi is actually considered a heavy fish load. Water changes are not necessarily considered the "gold standard" of pond keeping anymore. It's become a more common thought that regular water changes can be stressful to the fish and really shouldn't be done unless there's a compelling reason. Having said that, there are still lots of pond keepers who believe they are important and continue to do them, so you would be in good company either way. Just something to think about. And overall, water changes are far less important than maintaining an appropriate bio-load for a healthy pond.

 

[kmarcel]

Thank you Ray. I will hold off for a week since that’s how long for the praziquantel treatment. I did notice last evening that the fish was isolated again and seems as though it’s gulping. It hangs near the waterfalls with its head at the surface and body hanging down if that makes sense.

Lisak, five fish may be a heavy load but it’s the fewest I’ve ever had.

I wasn’t aware that the school of thought had changed on water chamges. I’m really surprised about that. Maybe instead of getting out the pump and hose, I will do water changes by doing a backwash and them adding water lost by the back wash. When I put the hose on spray to add water the fish always are very playful in it. I can’t imagine that it stresses them. Thanks for the info.

 

[Lisak1]

I can’t imagine that it stresses them

It's not mentally stressful - it's physically stressful in that their bodies have to adjust to the new water constantly. Mature pond water is a gift we give our fish!

 

[kmarcel]

Is there a difference in fish? To me if they are lively and keep swimming in the waterflow of the hose, their body is enjoying it. Not sure what their mind thinks.

That being said I don’t believe in big water changes unless there is a reason for it. I don’t think I could ever go without doing a water change at least biweekly, especially since my pond is small and being a closed system

 

[Tula]

I do "water changes" when I back wash the filter and I also top off the pond if it's low due to evaporation.

My pond is 1700 gallons and I used to have more fish. I now hold steady at 4 and catch and rehome the off spring each year....which is a total PITA ! ha ha !

 

[Lisak1]

Is there a difference in fish? To me if they are lively and keep swimming in the waterflow of the hose, their body is enjoying it. Not sure what their mind thinks.

No. What I meant was they probably do enjoy the spray of the hose - mine do too. But too much new water added to the pond requires them to physically adjust which can lead to physical stress. There was a thread posted here once regarding this subject- I'll see if I can find it!

Here you go - lots of interesting information on both sides of the water change theory:

Question on water change

I was wondering .... doing water changes, is it best to first drain the water and then replace it, or have running water going into the pond on one end, while pumping water out on the other end? I understand that doing it the second way gives no idea of the percentage of water exchanged, but...

www.gardenpondforum.com

 

[kmarcel]

I will now just do back wash and top off when water is low. Makes my life a lot easier. It's funny that I never really did water changes for many years, except in the spring until. Then I joined our local koi club (no longer in existence) and everyone said how important they were and I have been doing them for a the past 6-7 years. I have also read on many sites how important it is since backyard ponds are in a closed system as opposed to natural ponds which may be lake or spring fed. It's a whole new way of thinking.

 

[Lisak1]

Koi ponds are a different breed than garden ponds. We've frequently discussed the difference between the two types of ponds here. Your typical DKP (dedicated koi pond) would never have rocks or plants in it for example. They tend to have a heavier fish load and amore sophisticated and extensive filtration systems. Lots of things that make them different than an eco-system pond. And yes, it's a "closed" system, but not closed in the way an aquarium is closed. But the water changing philosophy seems to be a carry over from the aquarium model nonetheless.

 

[Ray G]

So to support the idea of not doing water-changes I have 12 koi and never do a water-change unless it is a byproduct of siphoning junk of the bottom of the pond. So I would never change the water in my pond just to do a water-change.

 

[mrsclem]

I also have stopped doing water changes. Flush filters and top off.