How to Treat Camallanus Red Worms in Aquarium Fish

Fish diseases can be notoriously hard to diagnose, but one of the more easily recognizable illnesses is an internal parasite called the camallanus red worm. Aquarium fish can be infected by a variety of nematodes and roundworms. They feed by attaching to the intestinal walls and can often co-exist with their host for a long time. However, additional stress factors such as poor water quality and aggression from tanks can weaken the immune system. This could lead to serious damage or even death.

Red Worms in Fish?

For a while, the fish will look quite normal in the beginning stages of the disease. You may notice that the juvenile fish grow slower than normal, the adults are not breeding as often, and eventually, you will lose a few fish every month. A loss of appetite was also reported by hobbyists.

The telltale sign of this sickness is when you see one or more small, red worms coming out of the fish’s anal vent. It can look like a cluster of little, scarlet threads sticking out about 1/4 to 1/2 inch (0.6-1.3 cm). The disease has reached a very advanced stage and the fish might appear abnormally thin or swollen from the worms. Secondary infections can occur when worms block the intestines.

Camallanus worms can be more easily seen in small livebearers, such as guppies. It only takes a few larvae to cause serious damage in a tiny fish. It takes worms longer to reproduce to a size that can take down larger fish like angelfish.

Guppy with camallanus Worm protruding from anal vent

What Are the Causes of Camallanus Red Worms

Infected fish can be introduced to an aquarium and the larvae of worms are passed on to the fish. These larvae are then eaten by small crustaceans such as cyclops. Healthy fish will eat the infected crustaceans. The larvae become adults and can reproduce in the fish’s body. Some species do not require an intermediate host. In fact, fish can be infected simply by eating fish feces containing larvae. Cross contamination can also occur when plants, gravel, and equipment are added to infected tanks.

How can I get rid of Camallanus Worms

Fritz Expel P, which contains levamsole and targets roundworms like camallanus, is a good dewormer. The medication paralyzes the adult worms, allowing them to be removed from the fish via an aquarium siphon. Follow the instructions on the package and use 1 packet Expel-P for every 10 gallons (38 liters) of water. After 24 hours, perform a 25% water change to remove the excreted parasites. Since levamisole does not affect unhatched eggs, wait two weeks after the initial treatment and then dose the tank again with Expel-P to deal with any remaining worms.

Fritz Expel – medication for parasitic conditions

Some articles suggest putting the dewormer inside food and giving it to the fish. We prefer to treat the entire tank, as sometimes fish lose appetites and you don’t have control over how much medication each fish consumes. Also, if your fish has secondary infections that need to be addressed, consider using broad-spectrum antibiotics or antifungal treatments as needed.

Besides medication, the key to recovery is lowering stress in the aquarium or hospital tank. To help the worms get rid of their toxins faster and gain weight, feed them high-quality food. Keep the water quality high and vacuum the substrate more frequently to remove any paralyzed parasites. To stop disease spread, disinfect any siphons and nets.

Dosing Expel-P in a package

How can I prevent Camallanus Worms from getting my house flooded?

Before introducing new fish to your aquariums, we recommend that you quarantine them for a few days to observe their behavior, appetite, health, and general health. While the trio of antibiotics can prevent most infections (bacterial, fungal, or parasitic), you should consider using Expel-P to treat specific concerns. Red worms can be tolerated by most fish for some time before becoming problematic. Keep the tank clean and provide fresh food. You can avoid cross-contamination by keeping the quarantine tanks in separate areas, washing your hands after touching the tank, and using separate siphons and nets to quarantine fish.

For more information on fish diseases, check out our collection of articles to learn how to identify, diagnose, and treat the most common illnesses.

Attributions 190729 Guppy 01 by BlueBreezeWiki (CC BY-SA 3.0)