Lymphocystis - Info and Cure


Well-Known Member
Many hobbyists have come across this viral infection. I thought I'd provide some general information and what the hobbyist should do.

Lymphocystis is a common viral infection of ornamental marine (and freshwater) fishes, caused by a number of related viruses. Most hobbyists refer to this as "Lymph" although honestly it's mostly because it's a hard word to always spell correctly AND remember! Lymphocystis is not fatal unless just totally ignored and the fish is being extra stressed from injury, illness, bad water quality and/or poor nutrition. You of course want to be sure you are in fact dealing with this virus. There are plenty of photos on the Internet for you to see marine fishes with this disease. Many are at various stages. In words: The virus infection displays on the fish by forming clumps or nodules. They are white to pink and take on a shape like that of a cauliflower or mulberry. These clumps appear on the top of the fish's skin, often found on fins, from pinpoint size to a few mm. They almost 'call to you' to just pick them off! Some are small -- 1 mm or less in size -- majority of them are medium in size -- 2-5 mm in size -- some are larger.

These viruses can live in water without a host for at least up to one week, so far that has been shown in research. The virus is transmitted to other fishes through skin and tissue abrasions (cuts and tares). We probably see nodules where the virus first got a food hold, but this is just my opinion (just so you know the difference between opinion and the facts I present here). However, under microscopic examination, other dermal cells of the fish show infection. So just don't fall into the trap of thinking the virus is just where you see the clumps -- it's all over the fish.

Some cultivated and wild fishes are found to have these latent viruses in their system. Add to this a long incubation period (up to several months), and the ease of contracting these viruses, and it may seem to the untrained and uneducated person that all fish have it. OR, because of a long incubation period, the fact that not all infected fishes will display having the virus, some people deduce that the disease is not contagious!

The viruses spread through cuts, tares, or abrasions on the fish. It needs a path to get to the fish's skin, beyond the mucous coating. Since fin cuts and tares are relatively common in netting a fish, this seems to be a prime means of a fish getting the disease. But, it's hard to tell from just observation, whether a fish is infected or not -- until it displays.

Infected fishes may never display the nodules! When the fish is captured, handled, netted, transported, etc., etc. is when the infected fish is stressed to the point where the virus will display. In the care of the hobbyist, the virus can display when water quality, environment or feeding is poor (or any combo of these).

The virus can transfer to other, uninfected fishes. If the uninfected fishes are in top condition in high water quality, they will not likely contract the disease. Also, even if the healthy, unstressed fish does get infected, it may never display. In these ways, this virus has some similarity to the human common cold virus. Being exposed to someone with a cold doesn't give you the cold. Many humans have the cold virus in their system, but until stressed or 'run down' the symptoms don't display. Another good analogy here is thinking that the human cold is just in the nose because that is where the symptoms are. Noted above, just because you see the nodules on the fins for instance, doesn't mean that is just where the virus is located.

This group of viruses is unusual. First, these viruses are in the 'self-limiting' category of viruses. When conditions for the fish improve, the viruses go into regression. Not necessarily cured, but the fish no longer displays the nodules. It is up to the hobbyist to prevent the display of this virus by providing high water quality, the proper nutrition, and the proper environment (proper water changes, maintenance of filters, clean up routine, community where fish is safe and not bullied, etc.). Another feature they have is that they are of the higher forms of typical viruses. Not the simplistic kind that children are taught about in high school.

I have had hundreds of marine fishes over the years displaying Lymphocystis. First thing to do with an infected fish is to remove as many of the stresses on the fish as you can, or at least significantly reduce the stresses. This means:

1) Isolate (quarantine) the fish if any of these things apply:
- i) Fish is covered in many areas with nodules;
- ii) Fish is being harassed by other fish;
- iii) Nodules on the fish's mouth hinder it from eating normally; and/or
- iv) Fish shows signs of secondary infections or disease
2) Improve water quality; and
3) improve environment (clean up, return to proper maintenance, check filters and keep clean, clean out detritus in the entire system, etc.).

The next thing to do is to improve its and all the fish's diet. This means:
a) Provide the proper diet and feed enough food, frequently enough;
b) Use fat and vitamin supplements, especially the right kind of vitamin C (see link below);
c) Use immune boosters (; and
d) Wait it out.

Remember, a fish displaying this is because it has suffered in your or the previous people's (poor) care that have handled this fish. The fish is stressed, maybe slightly injured. Helping the fish get better will require taking ALL the above actions, just not picking and choosing the ones you want. If the hobbyist is successful at addressing all the above and doing it all diligently, the fish will stop displaying Lymphocystis in anywhere from a couple of weeks to a few months.

If it was necessary to isolate the fish, then treat with an antibiotic. The antibiotic does not cure the fish of Lymphocystis, but will prevent other bacterial and opportunistic pathogens from gaining any foothold. I would recommend treating with Maracyn Two for Saltwater fishes. Just follow directions on the medication.

Things that don't work or which pose additional problems include:
I) Trying to get cleaner fish or cleaner shrimp to 'clean' the fish of it;
II) Trying to put medications into the water or trying to medicate the fish; and
III) Scraping the fish with a human fingernail or an instrument. (This will break nodules and send the virus into the water in large numbers, and possibly cause more abrasion to the fish's skin which just means more infection sites AND further stressing the fish).

Things that do help, but which are not necessary to do:
A) Surgically removing the lumps (this require surgery (duh!) and anesthetizing the fish);
B) Isolate the fish (into a QT -- not a big requirement unless 1) above applies) ISOLATE ALL FISHES WITH EXTENSIVE VIRAL INFECTIONS OR WHICH MAY BE DISPLAYING SECONDARY INFECTIONS;
C) If isolated in a QT, swab clumps with Betadiene disinfectant every other day (this requires anesthetizing the fish); and
D) Obtaining the Neon Blue Goby (Elacatinus oceanops). These fish sometimes actually eat it off of some displaying marine fishes (not a cure, just removes what you see for the time being).

It is a poor hobbyist that acquires marine life to 'fix' another fish's or tank's problem, with the exception of clean-up crews. So don't run out and buy a Goby. Just address the things you should and, like the human cold, wait it out.


Lymph is not one virus. It is a group of similar viruses. (I don't mean that the whole group is infecting at the same time -- it could one from the group, or any number of that group). These viruses aren't your normal ones. We don't know a whole lot more than what I've shared above. It's just not a virus investigated heavily. After all, it usually doesn't cause any mortality among the group of fishes it infects and it goes easily into regression.

The incubation of the virus can be days to months! So it would appear that it is not contagious to some observers. It also requires the fish be under certain stresses. So not seeing the display of the infection in a grouping of fishes when one is displaying in an aquarium, would be the anecdotal information others would use to claim it isn't contagious. This is one of the problems of relying upon anecdotal information. However, (this is important) in aquariums that contain a fish displaying Lymph, they have found these ('living') viruses in the water. Lastly, the means of transmission has been identified scientifically. It's contagious. So why not isolate all fish with this condition? Because most likely the other fish have been infect with it by the time you see the nodules on the one fish OR they won't get infected because they do not have abrasions, OR they don't display because they aren't stressed.

Latent forms of this virus are considered present in many kinds of fishes, both wild and cultured. That is, the virus is just waiting to become active (also noted in the above). After a fish is infected, displays, then the display goes away, some fish seem to have a temporary immunity to the virus. Others will display the nodules again when stressed.

To quarantine or not? The 'higher road' is to isolate the fish. But with the latency rate considered to be on the high side, the long incubation period, the causes that bring it forth being stress (and thus controllable), and the usual fact that it doesn't cause death, I believe the other fishes won't display this if the hobbyist takes actions to reduce the stress and improve nutrition for all the fish in the system. So, I don't recommend or insist the hobbyist to put the displaying fish into a quarantine tank. There are exceptions to this recommendation, which I've noted above under 1). Sometimes isolation is in the best interest of the fish. If the hobbyist wants to be conservative, then putting the fish into quarantine is fine -- no harm done. Just remember that a sick fish can sometimes be picked on by those fish that are healthy, so the hobbyist must diligently watch to be sure the displaying fish is not being mistreated in a community of fishes. If the hobbyist is unsure about detecting this, can't, won't or unable to do this, then proceed to put the fish in quarantine.

The real risk of this infection is that it may lead to secondary infections. The fish is signaling that it is stressed. It may be or recently has been injured. This just 'begs' the opportunistic and obligate parasites to come on in and take up residence.

Hope this helps! :thumbup:

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Well-Known Member
Regarding photo. . .I'm sensitive to copyrights and ownership issues. I have no photos of my own -- not being a particularly capable photographer. But the Internet is over loaded with them! :)


New Member
Thanks for all that info. I have a thread going on right now about a molly in my reef tank that has a single white nodule. At first I thought it might be ich but she still only has one white spot. I also included a pic of her spot, if you think this might be Lymphocystis, I don't mind posting a picture of it here. Here's a link to my post which includes a picture of the white nodule:
Let me know if you think this might be Lymphocystis.


Hey Lee, I know it was suggested in my thread a while back that my clowns had Lymphocystis. Here's the thread. Anyway, you're more than welcome to use any of those pics, or any pics of mine for that matter.


Well-Known Member
do you have any tips for this problem? i lost my true percula yesterday to lymph. D: It got to his mouth and he wouldn't eat a thing!! It wasn't even outside of his mouth, i just saw a giant swell in his upper lip and just before he died it was even growing outwards and over his lip. I had him for about 2 months, and he did amazingly. Then i lost a coral beauty, which i think triggered a chain reaction. Both clowns get brooklynella, then comes ich, black ocellaris dies, i qt percula, treat with copper, ich goes away, then he gets three white cysts. I removed them, but i couldn't do anything to get him to eat. HELP!!!


Well-Known Member
I am sorry to hear of your loss.

As the first post in this thread indicates, it is rare for any fish to die from this condition. It is like the human common cold. Few humans die from this, but it is possible. So why would or could a human die from a common cold? Poor nutrition; under much stress; not being able to rest properly; secondary problems; or any combo of these. It is the same for the fish.

You can only address the causes and help the fish heal itself. I don't know the particular case of your fish, ibimiiniblue, but the above is what to do. Actions have to be taken to reduce stress from all sources (water quality, tankmates, environment, etc.), improve nutrition (right foods, fed often enough), stability of conditions (pH, temp, salinity, etc.) and any combo of these.

To best understand this particular case you have to play detective and find the where's and how's your fish was stressed.

Ugly Stik

New Member
Hello Lee, I know this thread is old but im hoping you are still around to help me out. I have searched for a diagnosis for my Green Texas cichlid recently bought through an online dealer for awhile now. This thread sounds like what I got. I am knowledgeable in most fish diseases that I have encountered but this one I have not so it was hard to figure out at first. If this is not what My cichlid has maybe you could help identify what the problem is or anyone else here that might know. The Fish has some sort of lumps on the base of both its pectoral fins and back towards its tail fin a smaller one buy the small black dot.

Mike Johnson

Well-Known Member
I'm pretty sure that I read somewhere that Lee Birch was going overseas to work. I am not implying in any way by answering this post that I can take his place. I do, however, have a couple degrees in biology and specifically one in Marine Biology. So, I figure I can answer this question.

Yes, the photo you have posted is a perfect example of what Lymphocystis looks like.


JoePa lives on!!!
Staff member
Hey ugly, lee left a few months ago to work in the field...... Hopefully someone else can help!

Ugly Stik

New Member
Thank you so much!! Now since ive read that there is no way to cure it, but let it run its course and try to build up the fish's immune system and keep good water conditions. Is my royal pleco in the same tank in any danger? I read an article online that a fish carrying this virus can only give it to fish of it own kind. I dont know how true that is. Only solution I have is to put my royal pleco and my gold nugget together and hope they don't become to territorial since at the moment I dont have a quarantine tank

Mike Johnson

Well-Known Member
If you read the article through thoroughly you'd also see that everyone of the fish in that tank most likely already have it. There is a long incubation period before you actually see signs of it. Also, Lee Birch says to put them in a QT tank just for their own safety - like the other fish picking on it, or in extreme cases. Just follow the advise in his article like making sure the fish gets good nutrition and having good quality water. It is a stress related disease.

Ugly Stik

New Member
Thank you for all your help Mike. I did read it all the way through but also read other articles about it. Thats why I question about if it only affects fish of the same kind or not. I will follow everything on here. The fish is not being picked on. It is in a tank with my royal pleco that's petty small. I am pretty sure the stress that caused all this was from it being shipped to me. the seller I bought it from sent it regular mail and it took 48 hours to get here. Instead of the normal overnight that im use to when purchasing fish online. Where i am from LFS's dont carry nothing like i want so i am stuck buying online :( And again i thank you for your help :)

Mike Johnson

Well-Known Member
In that case I'd reconsider ordering another fish from the same seller. It takes a long time for it to develop into that stage and it implies to me that the seller has less than desired water chemistry.