Red, protruding lesion, what is it?

[SimonW]

Hello friends:

I have moved all my koi inside for over-wintering. All koi are closely inspected, and no visible lesions or other abnormality are found except one koi. Of course, if any of my koi would be sick, it would be my best koi ).

The lesion is local, red, protruding. It is on both sides of its belly (almost symmetrical), between the belly fins and the anus. It seems to be some parasite that have embedded in the lesions, but the strange thing is that none other koi has this problem.

Water parameters:

Ammonia: 0,
Nitrite: 0.1 ppm (remedied with some 0.3 % NaCl)
Nitrate: 10-20 ppm.
pH: 8
KH: 6 dKH

The only thing that can cause problem is the low temperature: It has been 3-4 centigrade for about 2 weeks now. May it be koi pox though not white?

Now the koi are in-doors, and the temperature is 19 centigrade.

By the way, these koi were infested with fluke, costia and chilo in June this year. They have first been treated with trichlorfon without success (I bought this medicine many years ago therefore it may had lost effectiveness) then 0.9 % NaCl for 3 months (gradually reduced to 0.4%), which seems to have killed the parasites (the koi stopped flashing completely).

Thanks for your thoughts and advice!

Simon



.

[montwila]

Carp Pox can become infected and might explain the color with the veining underneath. Since it is only one fish CP is the direction I would think.

Could it be left over irritated areas from flashing?

[SimonW]

Carp Pox can become infected and might explain the color with the veining underneath. Since it is only one fish CP is the direction I would think.

Could it be left over irritated areas from flashing?

Thank you for your thoughts!

Probably not, as they never had developed any lesion when they were flashing. They were not heavily infested, as I did many scrapings on them but only found very few flukes (maybe 1 fluke per 5 scrapings) and very low number of costia and chilo (if they were costia and chilo, like max 10 tiny, barely visible moving things per scraping). The parasites were mostly found on smaller koi that had lived together with them.

I stopped checking them since about 1 month back, as they no longer flashed.

[KoiRun]

I would agree with Monte that it is likely carp pox. I also agree with your assessment that it is likely carp pox since carp pox is seasonal and is common in the fall and winter. Why it is red is also perplexing to me. I know koi heals fairly quickly in warm water. Perhaps the lesions were lighter in colour and a soon you place her in a warmer environment the immune system went into hyper mode injecting blood vessels to fight fight the invader and to develop new skin underneath. Once through with process of healing, you should see skin peeling (shedding of the dead outermost layer). I tend not to scrape off these lesions prematurely as I think it serves a protective layer while the skin underneath is healing. Carp pox tend go into latency in warmer temperatures, so I'm wondering if this koi has had a history of it in previous winters. Also, I'm saying carp pox but I think it could be a number of other viruses which behave similarly.

[RichToyBox]

It could be viral, but it appears to me to be more bacterial. It would almost surely be bacterial if it were on one side only as fish do scrape against surfaces and the scrape will become infected with bacteria, which do cause redness and swelling, similar to a scraped knee or minor cut. To find almost the same size lesion on both sides at a similar location seems doubtful, but not impossible. In the cold water an infection will take forever to heal and may have been there for some time, and now that the fish is inside in warmer water it could go either of two ways, get better or get worse. I think I would wait and see before doing anything, but I would have on hand some antibiotics if it gets larger or redder. If it is viral, there is nothing that can be done but wait it out.

[SimonW]

Hello Richard:

I have left the koi be as you advised. It has gone 6 days since I moved it indoors. Today I checked the lesions, and it has neither got worse nor better.

This summer I treated a small koi that got red lesions (you said that it was probably bacterial infection after fluke-attack). I treated the lesions with iodine topically, and after 3 treatment it healed completely. But I don´t know whether it was healed by itself after I had killed off the fluke, or iodine did wonder.

So I wonder if I should do iodine-treatment for this koi or leave it alone for one more week and see?

[RichToyBox]

An iuodine treatment wouldn't hurt anything. You might consider drying the wounds and applying Triple Antibiotic Ointment on the spots following the iodine treatment.

[SimonW]

An iuodine treatment wouldn't hurt anything. You might consider drying the wounds and applying Triple Antibiotic Ointment on the spots following the iodine treatment.

Hello Richard!

Thanks again for your advice!

Now I have treated the koi with iodine. I don´t have antibiotics, unfortunately.

I have scraped the lesion and under microscope I did not find anything that moves but some filaments. I guess that they are fungi?



I don´t have any anti-fungi medicine, but I wonder if the formalin-Malachite solution (from Kusuri) I have would be good against fungi?

By the way I wonder if you remove the scales at the lesions before you do topical treatment with iodine or any other medicine?

I also wonder how long koi can survive being sedated and out of water. How long is a safe guideline?

[RichToyBox]

The kusuri treatment will be good for fungi, as the best treatment is Malachite Green. Won't hurt to do at least one treatment.

Some remove scales if infected to get to the infection when treating, some lance under the scale to expel puss from the pockets under the scale, I never did either, so your choice.

As for how long the fish can be out to the water sedated, that is a good question. I never took it past about 10 minutes, but when trying to euthanize a fish with sedation, you will find the fish still has a heartbeat and gill movement for more than an hour.

[SimonW]

Update:

Two months later the lesion has finally healed, leaving some visible irregularities in the scale. But I think that they will disappear when new scale grows out.

What I have done:

1) Two treatments of the whole tank with formalin-malachite green, 1 week apart.

2) Two treatments topically with iodine, 2 weeks apart.