How to Treat Camallanus Worms


Apr 21, 2009
Newcastle, Australia
How to treat for Camallanus Worms

These worms are nasty little buggers and cause serious damage even death to any fish they infect.
Camallanus Worms are more common than thought of in the home aquarium, and can often be the cause if you have a few unexplained deaths in a short period of time. They do not discriminate when choosing a host and will infect any fish that they come in contact with. One of the problems with having Camallanus Worms in the tank is how quickly they can infect all fish in the tanks. This is because fish like to eat them, and once they have made their way into the intestines they lay their eggs and the cycle continues. They are also very easily transferred from tank to tank without your knowledge just by the using nets or other aquarium equipment for multiple tanks. Within a matter of days you can have all your tanks infected. For this reason if you do have or suspect you have fish with Camallanus then you should treat all tanks.

The best sign of Camallanus Worms is the red thread-like protrusions from the anus area of the fish. However there are other signs that the fish are infected. A sunken in stomach and not eating are also good signs that the fish is infected with an internal parasite.
This picture shows how the camallanus worms infected a 5cm Albino Bristlenose. With treatment this little fella pulled through and made a 100% recovery.
If you click on the pic, it will show up larger.

Now for the treatments.

There are plenty of different de-wormers on the market. Not all are available world wide, so you will have to have a look around and see what’s available in your region.

The most common form of treatment for this is to use Levamisole*. Levamisole is a great fast-acting de-wormer and is highly recommended for the treatment of internal parasites amongst fish. The dosage for levamisole is 2ppm. Or according to packaging here in Australia it works out as 1ml per 7 litres of aquarium water.

I personally have used and highly recommend Avitrol Plus**. It is a combination of Levamisole with a small amount of Praziquantel. It is available in both liquid form and in tablet form. For the tablet form the dosage is 1 tablet per 10 litres of aquarium water and for the liquid form it is 1ml per 5 litres (I have never personally used the liquid form).

Now that we have covered the medications and dosages it’s time to discuss the best plan of action while using these.

It is best to dose the tank on a day when you will be around. From the time you add the treatment it can take less than 6 hours for the worms to start being excreted from the fish. During this time you need to keep a vigilant watch on them. This is because both the above medications paralise the worms, forcing them to release their hold on the intestinal walls and then be passed out of the body. It does not kill them. They then fall to the bottom of the tank, and will become food if they are not syphoned out of the tank, then continuing the cycle.

This is the recommended course of treatment when treating with Levamisole or a Levamisole based medication.

Step 1.
Work out the correct dosage (the doses for levamisole and avitrol plus are above, for any other med please refer to the packaging) For levamisole and Levamisole based medications it is a dosage equivalent to 2ppm. Do NOT add extra. Adding extra of these meds will not speed up the process, it will only cause more stress to your fish.

Step 2.
Add the correct dosage and regularly check the fish from about 4hrs after treatment. The majority of the worms will be excreted within 24 hours. Make sure you vacuum up any that you can see lying on the bottom of the tank as they will get eaten, continuing the cycle. Do not do a water change now as you will only be removing the med from the water too soon.

Step 3.
Do a water change on day 3. This is because Levamisole takes approx 3 days to be absorbed and have the remainder excreted by the fish. Don’t do a large water change, just approximately 30% will do fine. Doing a larger one will only add more unnecessary stress on the fish.

Step 4.
This step is a relatively easy one. 2 weeks after first treatment, repeat steps 1-3 again. This is just to make sure that any eggs that may have hatched will be taken care of.

Step 5.
This is only recommended, it is up to you if you do it or not, but I recommend repeating the treatment again 2 weeks later. The treatment schedule should be: first treatment, 2nd treatment (2 weeks after 1st treatment) and 3rd treatment (2 weeks after 2nd treatment). I like to do this just to be 100% certain of removing all traces of these worms.

I have never lost one fish after finding out of this treatment and have never had another outbreak either.
Most fish will pull through unless they have been badly infected, in which case the treatment was started to late to help. Not all fish though will recover completely. I have had one fish a female Kingsizei, (which no matter how much she was fed, what she was fed, or her tank conditions) she never regained her health. She remained very thin. This was because she had been badly infected and the worms had caused serious injury to her intestinal tract. That is just another complication these worms can have.

If you suspect your fish of having these parasites, then start treatment as soon as possible to give your fish the best chance of a complete recovery.

* Levamisole is a bridwormer and therefore is available from most pet produce stores. Here is the link to an article on Levamisole Hydrochloride. It is a very indepth article.
**Avitrol Plus is also a birdwormer. It is available from most pet produce stores. I highly recommend it.

For more information on worms you can also check out this article
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Global Moderators
Staff member
Apr 22, 2009
Burrum Heads, Queensland, Australia
I found the worms in my angelfish male. Bought him months ago from a lfs in Brisbane.

Its a bit tricky to worm him as he has a tank full of fry atm.

I treated last night with Sykes BigL wormer 1ml per 7ltrs.
I have often used it moreso as a pickmeup tonic for fish but this is the first time I have targetted these particular worms with it.
Overnight I have retrieved two worms from the sandy substrate but he still has a whole bunch hanging out but they look longer and seem to be losening up.
Good news is all the fry and the couple of corydora wrigglers are all fine with no affects from the wormer at all. :)


Apr 20, 2010
Sydney AUS 2206
Information on how to treat is spot on !
great information to have handy for quick reference
"i once purchased a fish with this worm horrible experiance"
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Apr 21, 2009
Newcastle, Australia
Those closeup photo's of the worms are amazing Brenda :coolphotos:

That is good to hear that you have no ill affects with the fry. I have treated before in a tank with loads of bristlenose fry with no ill affects either.


Retired Staff
Apr 8, 2009
Live Blackworm dies if you add salt to the tank, would it work the same if you added salt to the initial Camallanus treatment?
Imo, salt is something you need to be careful with and I wouldn't recommend using it unless you really have to. If the meds above have no detrimental effects on the fish then I would use them.