Gill damage. Can what I'm seeing be caused by gill flukes?

[Angie Jones]

I was asked to scrape and scope some fish yesterday in a pond experiencing mass die off after introducing new koi from an auction with no quarantine. (Sigh....). Here's the situation. 8K gallons, large bead filter, UV and adequate pump. As of yesterday, only a few small to medium sized koi and a handful of goldfish. All showing lethargy and most either with ulcers and/or red, inflamed bodies. Two dead in the pond that died overnight. One large water lily. No rocks beneath the water line. Lots of recent water changes and three recent treatments of Broad Spectrum. Ammonia 0, Nitrite 0, pH 7.2, KH @ 3 drops. Salinity .07%.

As expected, no evidence of parasites killed by Broad Spectrum, but I found a significant number of gill flukes. Several easily found on each slide. I began treatment and my question is about the level of gill damage present in the attached pictures. Can this level of damage be attributed to gill flukes? Or do I need to be worried about something else in addition to the flukes? Bacterial gill disease? KHV? Would anything else cause this level of damage? TIA

[fly4koi]

https://www.koiphen.com/forums/showt...-Gill-Necrosis

which dealer if you care to share? I've heard some particular dealer is working on vaccinating the fish against KVH...

[Angie Jones]

https://www.koiphen.com/forums/showt...-Gill-Necrosis

which dealer if you care to share? I've heard some particular dealer is working on vaccinating the fish against KVH...

Not a fish purchased from a dealer. This pond owner had recently purchased fish at an auction and purchased from several different tanks so there's really no way to even go back and isolate where the infection came from. I doubt KHV simply because these were fish out of individual club member's ponds and I did see flukes. I would like to know if a heavy fluke infestation can cause this type of gill damage. If the answer is "no", then I need to keep looking for other pathogens too

[Angie Jones]

... and this fish was alive if that matters

[fly4koi]

Gill fluke can cause damage, are you treating for fluke?

[Angie Jones]

Gill fluke can cause damage, are you treating for fluke?

Thank you, yes this pond owner is now treating for flukes. I gave them a bottle of fenbendazole because that is what I had on hand. They will purchase another bottle to treat a 2nd time in 4-5 days

[aquaholic]

This looks like Gill Rot to me. Look up Branchiomyces images which is actually a fungus. The treatment is quite difficult unfortunately but salt and increasing dissolved oxygen levels will help the fish to breathe.

The fish behaviour for this is very similar to gill flukes but luckily you examined the gills as well.

[fly4koi]

https://drjohnson.com/symptoms-and-c...and-pond-fish/

[aquaholic]

It's very contagious as the fungal hyphae (strands) are easily caught up in other fish gill rakers and quickly spreads.
I have only seen/experienced this first hand once and it was terrible.

The treatment strength needs to be fairly high so short dip treatments in clean tank.

Clove oil to anesthetise the fish will also help. The clove oil micro globlets gather on gill filaments right where the fungus is and kills the mold - fungus.
You do need to be careful as oxygen uptake is already compromised. If you are up to it, removing the dead gill tissue will reduce further spread but it's horrific cutting out gills. Existing dead tissue will rot away and cause future bacterial and fungal outbreaks. And away the disease goes again.

[fly4koi]

What about PP dip?

[aquaholic]

PP or any anti fungal medication is good. Formalin, copper, acriflavin etc.

Formalin with Malachite Green - FMG is good but easy to overdose and can burn tissue. This burn won't be noticed for a few days later. It depletes oxygen so lots of aeration during trearment.

I personally find PP ineffective and depletes oxygen too. I like and use copper a lot but admit it's tricky unless you have experience and a copper test kit.

Acriflavin would be my best suggestion for inexperienced fish keepers. Ideally in a large glass tank allowing observation.

[Angie Jones]

What about PP dip?

I would definitely have done a PP treatment early if it were my pond, but this is probably beyond the ability of this pond owner and the fish are in too weakened a state for me to be comfortable doing it for someone else's fish sadly.

[Angie Jones]

PP or any anti fungal medication is good. Formalin, copper, acriflavin etc.

Formalin with Malachite Green - FMG is good but easy to overdose and can burn tissue. This burn won't be noticed for a few days later. It depletes oxygen so lots of aeration during trearment.

I personally find PP ineffective and depletes oxygen too. I like and use copper a lot but admit it's tricky unless you have experience and a copper test kit.

Acriflavin would be my best suggestion for inexperienced fish keepers. Ideally in a large glass tank allowing observation.

Broad Spectrum had already been used on three different treatments before I got on the scene without any apparent benefit so I would think that it is not a fungal problem.

[aquaholic]

Hello Angie,
Is that Microbe-Lift Broad Spectrum? So Malachite Green & Formalin medication?
If so, and if at correct dosage that would knock out gill flukes more effectively than fungal issues.

However you are still finding some flukes? So not sufficient strength apparently even for flukes let alone fungal.

If you have a microscope, the fungus is very easy to see.

Also for this particular fungal issue, you need much higher medication dosages than for body fungus/saprolegnia.

High enough to kill fish so short term dips are necessary.

[fly4koi]

I don't think FMG works well on flukes though?

[Angie Jones]

Hello Angie,
Is that Microbe-Lift Broad Spectrum? So Malachite Green & Formalin medication?
If so, and if at correct dosage that would knock out gill flukes more effectively than fungal issues.

However you are still finding some flukes? So not sufficient strength apparently even for flukes let alone fungal.

If you have a microscope, the fungus is very easy to see.

Also for this particular fungal issue, you need much higher medication dosages than for body fungus/saprolegnia.

High enough to kill fish so short term dips are necessary.

I don't know what brand of formalin/malachite green medication they used, there are several brand names but I do believe the pond owner has an accurate knowledge of their pond volume and dosed correctly. In my original comment, I said that I was asked to "scrape and scope" these fish, so yes I do have a microscope. I was not familiar with this fungus but I googled it based on your comment. I don't recall having seen that structure under my scope but thank you for mentioning it, I now know to look for it in the future. Also, the formalin and malachite green chemicals don't kill flukes at any strength. You have to use an anti-worm medication for flukes which the pond owner did start medicating for the day I was there.