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Tackling Turtle Parasites In Pets

Unlike other pets such as dogs, cats, birds and other reptiles, turtles are less prone to parasites, both internal and external. However, when they do occur,  parasitic infestations need to be taken seriously as they can lead to serious complications and even death when left untreated.

Pet turtles are particularly affected by internal parasites also known as endoparasites. The common internal parasites to expect in turtles and tortoises include nematodes, tapeworms, flukes, and flagellate organisms.

In recent years, studies have shown that both captive turtles and wild turtles, including species like red-eared sliders, loggerhead turtles, and green turtles, are at potential risk for parasite infestation. Parasites can play an important role in the health of these reptiles, impacting species of turtle such as green sea turtles in various habitats, including those found in the Canary Islands and Southern Hemispheres.

We will go through the symptoms to expect and the course of action to take. With proper sanitation, a nutritional diet, and regular physical exams, pet turtle keepers can keep parasitic problems to a minimum.

Also, if you suspect that your turtle has parasites contact your local herp vet as soon as possible.

Common parasites in turtles

Turtle owners should be aware that turtles, being carriers of many different pathogens, can harbor different groups of parasites. This includes protozoan parasites and different species of ectoparasites, which are more commonly found in specimens of native species and exotic reptiles. The turtle’s immune system plays a crucial role in combating these parasites.



The first parasite we will look at is nematodes. Nematodes, including common types like oxyurid eggs, are among the most prevalent parasites in turtles, affecting various reptile species. These parasites have an established prevalence in various species, including green turtles and loggerhead turtles (Caretta caretta). Nematodes are endoparasites (meaning they are found inside the turtle).

Nematodes are more common among large communities of turtles. This parasite is comparable to the common roundworm which infects mammals including humans.

Nematodes are passed on from one turtle to another through fecal droppings. When a healthy turtle comes into contact with the fecal matter of an affected turtle, the nematode eggs can be transferred to the healthy turtle.

These eggs later hatch and develop into larvae which later develop into adult worms. These worms reside in the turtle’s digestive tract where they live and reproduce.

The eggs of this parasite leave the turtle when the turtle passes fecal matter. These deposited eggs end up in neighboring turtles thus spreading the parasitic infection.

Symptoms of a serious infestation include vomiting of worms, diarrhea, and weight loss.  If you notice these symptoms, it is best to consult your vet who will proceed to diagnose your turtle. The vet will examine a fecal sample under a microscope. This way the worms can be properly identified.

The doctor will prescribe a treatment for the turtle. The turtle is generally treated with the oral administration of an antiparasitic drug. The dosage is determined based on the weight of the turtle. A common antiparasitic drug prescribed is fenbendazole.

External parasites

External parasites, such as mites – ophionyssus natricis (common snake mite), play a significant role in the health of turtles. These parasites are often the result of poor capture techniques or direct contact with infected specimens. Preventive measures against external parasites are vital for any responsible turtle owner, especially in species like the green sea turtle and red-eared sliders.


tapeworm (cestoda)

These endoparasites are known as cestodes and affect all types of animals including mammals and reptiles. The type of tapeworms that affect reptiles including turtles is hermaphroditic and non-host specific.

Generally in turtles, tapeworms aren’t serious and infestations are uncommon since the parasite needs an intermediate host. With proper care, tapeworm infestations rarely happen.

However, they do occur. You may notice what appears to be moving grains of rice in the turtle’s fecal matter.  These are actually segments of tapeworms. Also, the turtle may show weight loss. Since infections are usually mild, you may not witness any of these physical symptoms.

Diagnosis of turtle tapeworm is tricky as tapeworm eggs aren’t shed as frequently in fecal matter. If you do notice a thin white translucent string-like worm, you can place it in a tiny container with some rubbing alcohol for the vet to examine.

As with any internal parasitic worm, tapeworms can be eradicated using dewormers. However, an overdose can lead to serious problems and even fatality.

Your herp vet will weigh the turtle and prescribe doses to it according to the weight. Praziquantel is quite effective for the treatment of tapeworm infestation in turtles.


Blood Fluke

This is another parasite that is not uncommon among captive-bred turtles. Fluke worms are also known as trematodes and they can be found in the intestines of reptiles including turtles. They can also infect other organs including the liver, kidneys, and lungs.

Except for blood flukes that are found exclusively in sea turtles, flukes rarely cause death. Flukes can be diagnosed by finding their eggs in fecal matter.

Treatments include the oral administration of dewormers such as praziquantel or fenbendazole. As with other treatments already mentioned, the dosage must match the turtle’s weight.

Flagellate organisms

Flagellate organisms found in pond water under microscope

These are protozoans. They are worm-like organisms that can be found in the intestinal tract of several reptiles including aquatic turtles and tortoises.

Generally when present in moderate numbers they are benign. It is only when flagellate organisms such as Trichomonas are found in large numbers, that you need to worry.

Symptoms of severe trichomonas infestation include weight loss, dehydration, diarrhea, and the passing of undigested food.

A herp vet can examine the presence of flagellated organisms in the fecal matter of the turtle and decide the course of treatment needed.

The most common treatment for severe infestation is oral administration of metronidazole. This drug, however, has the negative side effect of killing beneficial microorganisms as well.

An adverse increase in flagellate organisms may be down to dietary deficiencies. High sugar intake can also cause increased levels of flagellate organisms.

It is not advisable for fruits to be a staple in your turtle’s diet. Offer fruits only as treats. Other causes of flagellate organism infestation include overcrowding and excessive heating.

Ensure the enclosure isn’t overheated. It’s a good idea for heat lamps to be off during the night.

Symptoms of a parasitic infection

Specific symptoms of parasite infestation in turtles can include loss of appetite, behavioral changes, and physical signs like the presence of endoparasites visible to the naked eye. Regular monitoring of the turtle’s feces and behavior is crucial to identify these symptoms and prevent serious health problems.

While it is true that different parasitic infections manifest in many different ways, here are some common symptoms to watch out for.

  • Dehydration
  • Diarrhea
  • Passing undigested food
  • Vomiting
  • Weight loss

If you notice two or more of these symptoms, then your turtle may have a parasitic infection. Even just one of these symptoms is a cause for worry. I believe it’s always best to contact a veterinarian when unsure.

Diagnosis and Treatment

If you suspect that your pet turtle has parasites, it is best to have a herp vet examine it. Usually, the vet must examine a sample of the turtle’s fecal matter under a microscope.

This microscopic examination should help the vet to identify the culprit and prescribe the right treatment. While dewormers are prescribed for most internal parasites, it is unwise to try to deworm your turtle without consulting a vet as wrong dosages can kill the turtle. The right dosage is calculated using the turtle’s weight.

Tapeworms and flukes are generally treated with praziquantel or fenbendazole. Protozoans are generally treated with metronidazole. And nematodes are usually treated with fenbendazole.

Small worms in the tank

It is not uncommon to notice what appear to be tiny black worms in the turtle’s tank. These wriggly little worms may look nasty but they generally cause your turtle no harm.

They are most likely insect larva and can be found in stagnant puddles as well. They may also be annelids, particularly detritus worms. These tiny worms aren’t harmful and fish even feed on them. These may also resemble tiny white worms in the turtle tank.

These tiny worms in the water are generally harmless. If they wiggle a lot and are active then they may just be harmless detritus worms or planaria. You’ll most likely notice them when you clean out the filter.

They are more common in turtle tanks with river pebbles or gravel as the space between the stones allow for organic waste to build up out of sight. The worms thrive on organic waste.

It is important to remember that eventually, every large tank will have small invertebrates living in them. If you want to get rid of them, you can use a much larger filter, replace the filter media regularly, and change the water in the tank more frequently. Also, never leave uneaten food in the water.

A quick fix is to scrub down the tank with a bleach solution and clean the filter and the substrate with a bleach solution.

Research and Studies

Recent studies by graduate students and turtle experts have focused on the exact reviews of the examined animal species, including turtles, to determine the best way for effective treatment and prevention of parasitic spread. These studies often involve blood tests and detailed examinations of internal organs to understand the presence and impact of parasites like trichinella papuae and trichinella zimbabwensis, particularly in endangered species.


Turtles and tortoises are less susceptible to parasites as other pets are  (including mammals, birds and even other reptiles). As such, your turtle can go through its entire life without having to deal with parasitic infections.

Regardless of this, there are several internal parasites that can harm chelonians. When left untreated, these parasites can cause severe problems.

If you suspect that your turtle is dealing with parasitic problems, it is best to contact your local herp/exotic veterinarian. With the right treatment, your turtle should be parasite-free in no time at all.

The aim of this is to provide a comprehensive overview for turtle owners on the importance of good hygiene in preventing the spreading of parasites. Proper treatment, including the use of appropriate medications, is essential for maintaining the health of pet turtles. Maintaining a clean tank and fresh water source are key preventive measures against different types of parasites.

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Tuesday 5th of September 2023

What should I do if my pet painted turtle will not eat and I have seen little white worms in poop?


Tuesday 5th of September 2023

@Julia, I have also noticed with trying to find a vet the nearest one near me is 4 hours away what should I do?


Sunday 2nd of July 2023

What are the tiny little red worms in the turtle water? I have never had a problem with them in the past 10 years. But the past two times I have changed and cleaned the tank, it has been infested! Can I get rid of them? I have attempted to completely scrub everything in the tank, inside and out, well. Any ideas?


Tuesday 4th of April 2023

Our aquatic red ear turtle has big balloon like bags bulging out around it’s back legs. One side bigger then the other. Looks real sad. We have no idea what is wrong nor what to do. No vets anywhere around. Closest one is an hour and a half away. Anyone know what would cause this problem?


Friday 12th of May 2023

@Mikh’el, from my limited experience & w/o a pic, it could be a number of things like obesity or maybe retained eggs(?) for example. I searched all over for a vet bc it was nesting season, my RES wouldn't bury her eggs, I felt round lumps on each side of her toward her back legs. I was worried she was holding her eggs in. Vet took an Xray and duh, it was her hip joints. I didn't realize they were so large. If you're RES is holding eggs, don't poke around too much, it could be fatal if one breaks inside her. Worst case scenario- keep consulting turtle forums & include pics & specifics. This could be time consuming & not give any real answers, but you might get lucky. Other option- try to find a vet site where real vets answer questions. Best scenario- contact a local vet that will give a video or phone consult or just make that drive & get it over with. Actual ballooning can't be good & might be very painful.


Monday 15th of March 2021

Hello, is it possible humans to catch parasites from turtles or tortoise?


Tuesday 8th of September 2020

OK sir