Betta Camallanus Worms: Symtoms, Prevention, Treatment

camallanus worms in Betta fish
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Adopting betta fish brings joy and excitement to your life because of their vibrant and aesthetically pleasing colours and captivating body movements.

However, you must take good care of them to keep them healthy and happy, as they’re susceptible to various health conditions and infections (fungal, bacterial, or parasitic).

Most of these conditions are treatable and preventable, but what about camallanus worms?

This article is a guide for betta owners about the causes of camallanus worms in betta fish, how they infect the fish, and what treatments can be applied to effectively deal with them.

In the last section, you will also learn how to prevent them in your bettas.

What are camallanus worms?

Camallanus worms are thread-like, small, red-coloured parasites from the genus Camallanus.

They can infect many freshwater fish species, including betta fish.

Although they can attack any internal fish organ, their main target is the digestive tract.

If these worms are left untreated for a long time, they may start emerging out of the fish’s anal vent after completing their lifecycle in the digestive tract.

Camallanus worms are also called red worms or camallanus red worms.

Like other species of the genus Camallanus, such as nematodes (roundworms), red worms can be extremely harmful to their hosts and may prove fatal in severe cases.

How do camallanus worms infect betta (Lifecycle of camallanus worms in betta)?

The infection mechanism of a camallanus worm is similar to other nematodes.

After entering the betta’s body, they attach themselves to the intestinal walls for feeding.

From there, their lifecycle starts and completes in three stages:

Stage 1:

Mature red worms mate in the digestive tract of the fish.

After mating, females give birth to first-stage larvae.

These larvae emerge from the fish’s body with faeces and settle in the bottom of the aquarium onto the substrate.

Stage 2:

Crustaceans in the aquarium consume these larvae and keep them in their gut until they moult into second-stage larvae.

These inactive larvae reside in the host’s gut without causing infection.

Stage 3:

When betta fish eat these crustaceans, the second-stage larvae enter their bodies and become active.

They begin feeding again and moult themselves twice to become sexually mature red worms.

Here, the lifecycle of camallanus worms completes.

Crustaceans act as an intermediate host for red worms, keeping them in their bodies in the larval stage.

Camallanus worms can reside in the body of their first host for long periods without causing symptoms or infection.

What causes camallanus worms in bettas?

Several factors can facilitate the entry of camallanus worms into your betta’s body, such as:

  • Contaminated (worm-affected) water

If your aquarium water is contaminated with red worms, your betta can ingest them while drinking the water.

Camallanus worms thrive in poorly filtered, uncleaned water, which contains high levels of ammonia and nitrates and excessive buildup of food leftovers.

Contaminated water is one of the most significant mediums for worms to enter in fish’s body.

It also provides a favourable environment for worms to complete their lifecycle in different hosts.

  • Infected fish

When fish infected with camallanus worms are introduced into the aquarium, they can spread the infection to healthy betta fish by serving as a carrier of worms.

This mainly occurs when new fish are added to the aquarium without being properly quarantined and checked for worms.

  • Poor diet

Poor diet causes malnutrition in betta fish, leading to the immune system’s weakness, making them susceptible to camallanus worm infection.

Betta feeding on an unbalanced, low-quality diet lacking essential nutrients may lose the capability and capacity to fight off red worms and become vulnerable to parasites.

  • Stress

Stress weakens the immune system of betta fish, making them an easy target for camallanus worms.

Any factor that triggers stress in your bettas can facilitate the entry of worms into their body.

Your fish may become stressed out due to poor water conditions, sudden changes in the living environment (change in temperature or pH), aggressive behaviour of tank mates, and poor diet.

Red worms cannot easily infect betta fish as long as their immune system works at maximum capacity.

However, when it becomes compromised, worms can quickly enter the fish’s body and rapidly multiply to cause severe infection.

Symptoms of camallanus worms in betta fish

As camallanus worms cause infection, most of their symptoms are similar to other infections, such as fungal or bacterial.

Here are some common symptoms you may notice in your bettas when they’re infected with red worms:

  • Redness and inflammation in the anal area

In severe cases of camallanus worms infection, you may notice a red or inflamed anus in your betta fish.

It occurs due to the irritation and discomfort caused by the worms.

  • Digestive issues (like bloating)

As the digestive tract is the primary attachment area for camallanus worms, your betta may experience various digestive issues, such as bloating, difficulty in food digestion, or swelling of the abdomen.

  • Paleness in gills

If your betta’s gills are pale or discoloured, it might indicate the presence of red worms in their body.

The paleness results from the reduced oxygen uptake caused by the worms.

However, gills can become pale due to several other health conditions like furunculosis, so it’s always important to look for other symptoms before concluding.

  • Worms protruding from the anus

In severe cases, you may notice the camallanus worms protruding from the fish’s anus.

The worms may also come out of the fish’s body with faeces. So, examining the faeces of your bettas fish helps diagnose red worms.

  • Loss of appetite and emaciation (weight loss)

Loss of appetite is a common symptom in fish suffering from an infection.

So, if you notice that your betta fish have reduced appetite or stopped eating altogether, it might be a symptom of an infection caused by red worms.

If loss of appetite prolongs, your fish may become emaciated (thin or over-slim).

  • Lethargy

Infected betta fish may show lethargic behaviour.

They become less active and spend more time resting on the bottom of the fish tank or hiding behind a decoration.

How to treat camallanus worms in betta fish

Many treatments can be applied for a camallanus infection in betta fish.

However, a treatment’s effectiveness depends on the infection’s severity and the stage of the worm’s lifecycle.

Here are some common treatments for camallanus worms in bettas:

  • Anthelmintic Medications

Anthelmintic medications are considered the most effective treatment for red worms.

The medications are parasiticidal drugs that retard the activity of camallanus worms and prevent them from infecting bettas.

Some common anthelmintic medications available in the market include fenbendazole and praziquantel.

You can mix the medication in the food of your bettas.

When they eat the medicated food, the worms absorb it, killing them over time.

However, this way of medicating is only possible when your betta is eating normally.

Anthelmintic medications retard body functions in red worms, causing them to become paralysed.

A paralysed red worm cannot attach itself to the host’s intestinal walls to cause infection.

Fish’s digestive tract pushes paralysed worms into the anus, from where they eventually release into the aquarium.

However, such medications are only effective if you correctly follow the manufacturer’s and your veterinarian’s instructions.

If your bettas have stopped eating, you can dissolve the medication in the aquarium water to treat them.

However, it’s less effective than mixing medication in the food.

Once you notice that red worms have started to emerge from your betta’s body, you should clean the substrate in the aquarium once a day with an aquarium siphon.

It will help you remove any worms accumulated on the surface of the substrate.

After medicating all bettas, you must also perform a water change and restore it to the usual water quality and parameters.

  • Quarantining infected bettas

Isolating your infected bettas in a quarantine tank helps you prevent the spread of camallanus infection to healthy fish.

It’s more like a preventative measure than a treatment, as it allows you to prevent the spread of parasites.

However, experts believe properly quarantined and medicated fish will likely recover more quickly.

So, quarantining your infected bettas helps in their recovery process from the infection.

  • Water changes

Performing water changes regularly can help you remove red worms and their larvae from the aquarium water.

It’s advised to perform a 25% water change every week to keep the water quality at the highest level.

Preventing camallanus worms in bettas

If you want to prevent a camallanus infection in your bettas, the first thing you need to do is to keep your fish tank clean and well-maintained.

That’s because red worms thrive and grow faster in a dirty, poorly maintained fish tank.

Besides maintaining your aquarium, you can take the following measures to prevent camallanus worm infestations in your bettas:

  • Quarantine new fish for 10-15 days before adding them to the main aquarium: Freshwater fish species are a significant carrier of camallanus worms. Therefore, you must quarantine them for at least two weeks before adding them to your betta’s aquarium. The quarantining period will allow you to monitor the signs of illness and parasitic infection in them, making it easy to prevent the spread of infection to the healthy betta fish.
  • Feed your bettas a balanced, high-quality diet: Your betta fish need a balanced and nutritious diet to keep their immune system working at maximum capacity. They may develop nutritional deficiencies from consuming a low-quality diet. Therefore, you must feed them a high-quality diet purchased from a reputable pet store. You can also prepare a customised diet for your bettas by consulting with your veterinarian.
  • Avoid overfeeding: overfeeding is a stress-triggering factor for your bettas as it leads to the accumulation of food leftovers and wastes in the fish tank, contributing to poor water quality. It directly contributes to the favourable environment for the growth of harmful parasites like red worms. Therefore, you shouldn’t overfeed your bettas.
  • Regularly quarantine and sanitise new plants and decorations before adding them to the aquarium: live plants and decorations can serve as a carrier of camallanus worms. Therefore, they must be properly sanitised before being added to the aquarium. You can use a good quality disinfectant or a bleach dip solution.
  • Monitor your bettas’ behaviour: Observing your bettas’ behaviour regularly can help diagnose a camallanus infection in its early stage, making its treatment easier. You should notice the eating patterns, body movements, and activity periods in your bettas and look for any signs of parasitic infection, such as loss of appetite, bloating, or lethargy. It’s also important to check for the presence of red worms in your aquarium water.


Camallanus worms are life-threatening parasites for your betta fish unless you treat them in the early stage of infection.

The common symptoms in your betta suffering from a camallanus infection include visible thread-like worms around the anus, loss of appetite, lethargy, and bloating.

You can treat the infection with anthelmintic medications available in the market after consulting with your veterinarian.

It’s important to keep in mind that camallanus worms have a high mortality rate, so you must act immediately if they’re diagnosed in your betta fish.

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