Case Report - It probably isn't Lymphocystis

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Submitted by Spike Cover on Sun, 09/18/2016 - 16:13

by: Spike Cover, June 8, 2010

When I had a fish that developed what appeared to be lymphocystis-like lesions (warty, rough and cauliflower-like), I “hit the books” and the Internet. Here’s what I found:

Koi keepers have been told that our fish can and do get lymphocystis. Erik Johnson writes, "Of all the viruses affecting Koi, perhaps the most common is LYMPHOCYSTIS.”1

However, an odd phenomenon has also been observed and reported, i.e., Acriflavine appears to “cure” it. Now we understand that viruses are not known to be cured by antiseptics like Acriflavine, so this makes little sense.

Interestingly enough, many in the Koi world seemed to echo the common belief that Koi can and do get lymphocystis and, that Acriflavine appears to be effective against it. Lance Jepson, an author that I’ve read and admired for a number of years wrote this regarding lymphocystis, “Most freshwater fishes appear to be susceptible, but members of the cyprinid (carp-like) family do not become infected.”2

Jepson went on to write, “… Another possibility is epihtheliocystis, which is a very different disease caused by a bacteria-like organism that infects the mucous-secreting cells of the skin and gills. Epitheliocystis is well recognized in cyprinids, such as carp; if lymphocystis-like masses are seen on these fish, then treat for epitheliocystis.”

On a web site, , Jepson also wrote the following:

Chlamidia-like organisms
Epitheliocystis is caused by intracellular, bacteria-like pathogens which have yet to be definitively classified. They seem to infect the mucus-secreting cells in the gills and skin of carp, where transparent or whitish cysts are formed. In large numbers they cause damage to the gills, and respiratory distress partially due to excessive mucus production. In carp, especially, there is a proliferative reaction, which can be associated with low temperatures, in which the surrounding tissues form a signicant [sic] fleshy mass. In appearance, Epitheliocystis can be difficult to distinguish from the viral infection Lymphocystis. However, Lymphocystis does not infect carp!

I was able to find other references to lymphocystis in other general fish disease books but none specified that carp became infected.3,4

Noga wrote, “Unlike lymphocystis, epitheliocystis can also infect salmonids, catfish, or cyprinids.”5

So, armed with this information, I took a fish from my pond that had a nose and head that looked like the first picture (just above) on the day I started its treatment (Tx):

I treated it with Acriflavine. About a week and a couple of treatments later, its nose and head looked like the picture just below - a huge improvement with the white patches appearing to be dead tissue that would fall off in the near future.

Here’s how I treated this Koi:

On May 31st, I put the fish in separate tank with 50 US gallons of pond water and about 4 fluid ounces of 2% Acriflavine solution in the water, for about 15 ppm Acriflavine. I left the fish soaking in there for about 2 hours. Then I filled up the tank to about 100 US gallons of pond water (diluting the treatment to about 7.5 ppm Acriflavine) and left the fish in that solution for several days with a heater and an air-stone in the tank.

On about June 4th, I put 50 US gallons of pond water into another tank with about 2.5 fluid ounces of the 2% Acriflavine solution into the water (making about 10 ppm). I let the fish “soak” for a couple of hours, then put it back into the first tank that I’d cleaned and refilled with 100 US gallons of pond water and 30 cc of dry (powdered) ClorAm-X. On June 8th, I took the second picture above and repeated the 50 US gallon, 2 hour soak and again put the fish back into 100 US gallons of fresh pond water with 30 cc of dry ClorAm-X.

BTW, a couple of months prior to the Tx described above, an ELJ recommended IP dose of Nuflor1 produced no apparent improvement in this fish. However, the water was much colder then, probably in the low 60 degrees F. The water during the Acriflavine Tx described above was in the low to mid 70 degrees F.

Here’s the, “So what?” as I interpret my literature search and the results of the fish treatment so far:

  • The claim that carp don’t get lymphocystis is likely true, and therefore my Koi likely did not have lymphocystis.
  • The contention that the lesions that look like they might be lymphocystis in Koi may well be a bacteria-like infection and a Chlamidia-type epitheliocystis, may be true. My koi may have had epitheliocystis.
  • Acriflavine can sometimes treat a disease that appears lymphocystis-like in Koi. It certainly had a very positive effect on my fish.

I’ll try to report the progress here on the K.O.I. web site as the Tx continues.


1 Koi Health and Disease, 2006 Reload – Johnson, E. (2006). Printed by Reade Printers, Athens GA
2 The Super Simple Guide to Common Fish Diseases, - Jepson, L (2004), THF Publications, Neptune City, NJ
3 Fish Diseases (5th corrected, revised and substantially enlarged edition) - Schäperclaus, W (1991). – A.A. Balkema/Rotterdam
4 Fish Diseases - Eiras, J., Segner, H., Wahli, T. & Kapoor, B. (2008) – Science Publishers, Enfield, NH
5 Fish Disease, Diagnosis and Treatment – Noga, E (1996), Mosby, St. Louis, MO


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