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Over the past 20 years keeping spiders (particularly tarantulas) as exotic pets become very popular. Some of the tarantulas are wild caught, but most are successfully bred in captivity.

Spiders are popular because of four main reasons:

- relative unpretentiousness and simplicity of keeping requirements;

- they do not need much space;

- prices for spiders and their food are quite affordable;

- large size, bright coloration and unusual appearance.

Almost all current information on the tarantulas’ biology was obtained as a result of observations in captivity, and only a small part of it is the result of natural research.

When buying the spiders people, especially beginners, often come across health problems. Unfortunately tarantulas’ diseases for today are poorly studied and there are very few ways to treat them. The purpose of this article is to share our experience concerning health problems, their prevention and treatment.

First step to prevent diseases is to maintain proper keeping conditions for any tarantula species. According to our experience, sick tarantulas have only a small chance for full recovery. It is important to diagnose the disease at early stage and start treatment as soon as possible.

This article describes quite common diseases easy to diagnose and detect. Also we will give you the prevention measures and treatment techniques (Bagaturov, 2001; Schultz, 2009).

1  Dehydration

Diagnosis. The spider sits on a drinking bowl or inside it, constantly occupies at the wettest place of the terrarium or tries to dig into the substrate. The spider presses its limbs under itself. In the later stages the animal becomes sluggish (fig. 1) and its abdomen wrinkles.

Fig. 1. Dehydration in Brachypelma spp. (photo from www.tarantulas.ru)

Prevention. Unconditional maintaining of required keeping conditions.

Causes. Low humidity level at the terrarium, absence of drinking or fresh water inside, long lasting transportation of the animal.

Treatment. Increasing of the humidity level at the terrarium by spraying; putting a drinker if the one was absent before (note: the drinker should be of suitable size, so that the spider can safely drink from it). If the animal can’t move itself, put it in the drinking bowl in such a way that its chelicera safely reaches the water surface. Abdomen of the spider must be on the dry land, otherwise the spider can "choke-bore", because pulmonary stigmas are situated on ventral part of spider’s body. In this position, the animal can be left for an hour. The same procedure should be repeated for next several days. When spider’s condition improves, you can start normal feeding (Jacobi, 2001).

2  Damage of the external covering

Limbs injuries are the most common problems in tarantulas.

Causes. Loss of limbs during molting, pinching of limbs with the terrarium lid, biting or limb detachment during mating (fig. 2) process are the main causes.

Fig. 2. Limbs loss in Brachypelma albopilosum (photo by Rainer Folix, Biology of Spiders)

Prevention. Clear and unconditional maintaining of moisture regime, the absence of objects that can fall down inside the terrarium and carefulness during carrying out various kinds of manipulations with your animals are essential aspects to avoid such problems.

Diagnosis. Droplets of hemolymph (translucent slightly viscous liquid) appear from small lesions, the animal pulls the limb not leaning on it.

Treatment. Treatment of the injury site should be done with the using of petrolatum or BF-6 glue. The animal is deposited in a clean terrarium with a drinker and without substrate (dry quarantine). If the damage is wet and does not heal within 3-4 days, the limb should be amputate in the area of trochanter’s ​​attachment to the carapace, clamping the limb with tweezers, to stimulate the spider to "throw" it out. Wound place is now treated with petrolatum or BF-6 glue. The limbs normally restore after 3-4 molts, depending on the spider’s age.

Damages to the abdomen and carapace are more dangerous, but much less common.

Prevention. The absence of objects that can fall down inside the terrarium and carefulness during carrying out various kinds of manipulations with your animals will help to avoid such injuries. Do not feed the animal if it is about to shed.

Diagnosis. Droplets of hemolymph appear from small lesions, large lesions are easily diagnosed by rupture of the external covering (fig. 3). It should be noted that it is rare to save a spider with such injuries.          

Fig. 3. Rupture of carapace during molting а) Brachypelma boehmei (photo from www.arachnoboards.com), b) Heterothele villosella (photo by Craig Mackay)

Treatment. If the lesions are relatively small it is enough to treat the injury site with petroleum jelly or BF-6 glue and dry quarantine. If the animal has fallen from a great height and the damage is more serious, the following measures should be taken. We moisten a clean cloth with water, put it in a microwave and heat it to dryness. After that we put petroleum jelly on it and close the wound surface and the animal is placed on a wet napkin in a clean box. If it was successful to stop the hemolymph flow, remove the petrolatum barrier and treat the damage with an antibiotic. Neomycin ointment (neomycin sulfate) has many times been proved to be very effective for this purpose. If the spider was successfully saved, the following problems would begin: between the new and old exoskeleton, a spike is formed on the healing site (scar) and therefore a new rupture may occur during the next molting. If all is good, such spiders should not be allowed to breed.

Molting problems also refer the same group of diseases.

This can happen from time to time with any spider, regardless of the keeping conditions.

Prevention. Clear and unconditional maintaining of the moisture regime and avoidance of feeding the animal if it is going to shed.

Diagnosis. The spider sheds for unusually long period of time, or molts with the limbs loss.

Treatment. You need to try to extract the spider from the old exoskeleton. For this you will need 2 eye tweezers, magnifier, nail scissors, good lighting and a pipette. First of all 2-3 drops of liquid detergent for dishes are dissolved in 250 ml of boiled water (Schultz, 2009). This solution is gradually applied to places where the spider has not passed through the rings of the old exoskeleton with a brush or pipette, so that the liquid drops do not fall on the stigmata of the pulmonary books. After 30-60 minutes, we check, whether the spider can free itself from old covers. We start from the carapace by gently picking its plates (they are connected to the old exoskeleton with thin strings) up and shifting them.  Then we see if they are removable at all. If not, then we find strands under magnification, dissect and remove them.  Now we can work with the abdomen. Usually after treatment with a solution the covers here exfoliate themselves. Working with limbs is a piece of jewelry work that requires experience and patience. It is impossible to determine how the new fragile limbs are attached to the old segments. Powerful rings, securing the segments of the old exoskeleton, should be carefully broken and removed with tweezers. At this stage, it is necessary to have at least a jewelry magnifying glass or a large magnifier. One should work consistently, releasing one joint and one leg at once.

3  Abdominal hernia

A hernia is a protruding, often growing formation, similar to a crust or a lump (fig. 4). Individuals of the Brachypelma genus are particularly susceptible to this type of damage (Schultz, 2009). As a result of overfeeding and maintenance on a rigid substrate, the hernia can cause a molt rupture in the abdominal covering. 

Fig. 4. Abdominal hernia in Brachypelma boehmei (photo by American Tarantula Society)

Prevention. Strict maintaining of the feeding regime and avoidance of using sawdust and gravel as substrate. The height of the terrarium walls must meet all needs of the species.

Diagnosis. Presence of a protruding, often growing formation, similar to a crust or a lump on the abdomen surface.

Treatment. The hernia site is treated with emollients such as glycerin, petroleum jelly.

4 Mycosis

Mycosis is one of the most serious diseases. Fungal infection is not common, however, with poor ventilation and excess moisture at the terrarium or the use of natural substrates, any keeper can come across it. Always pay attention to the presence of microscopic white, yellow, black or orange fungi on the substrate and interior objects (shelters, driftwood, etc.).

Diagnosis. Appearing of mold vegetation on the interior objects and substrate.  Black or brown spots on the animal's body (fig. 5) can in most cases be lethal to the animals. Getting a fungus spore inside the spiders’ lung book always ends lethally. The spore-bred fungi of the Cordyceps and Torrubiella genuses (fig.6, that are parasitic to arthropods, have been reported to repeatedly kill the tarantula, growing into the depths of soft tissues. They are distributed throughout Europe, so wood peat or soil taken from the park can lead to irreparable consequences.

Fig. 5. Fungal infection

Fig. 6. Infection of tarantulas with spore-bred parasitic fungi from Cordyceps and Torrubiella genuses (photo from www.theraphosidae.be)

Prevention. Maintenance of a normal humidity and ventilation regimes at the terrarium, monthly processing of scenery and other equipment (tools) with disinfectants. Do not use litter, soil or peat from a park or forest as substrate.

Treatment. Dry quarantine and treatment of mold foci on the spider’s body with nizoral gel or 1% clotrimazol ointment: the volume of the ointment equal to the match head is diluted in 5 ml of warm boiled water, until complete dissolution. With a soft brush, apply the solution once onto the fungus foci. We process the second applying session after 72 hours. This method was tested many times and proved to work well (spiders survived and normally shed later) on Lampropelma sp. Simon, 1892 (Borneo black), Brachypelma smithi F. O. Pickard-Cambridge, 1897 and Theraphosa stirmi Rudloff & Weinmann, 2010.


5  Mites

The terrarium may be invaded by mites with newly arrived spiders that have not passed quarantine regime, with insects, soil or decorations. The first thing you need to do is to make sure that it's exactly the mites, not springtails or something else, by observing them under the microscope or carrying them to relevant experts. If you have proved that your spider have exactly mites, there are two basic dangers. The first one is the strongest stress to the spider as the number of mites increases. The second danger is the ingestion of mites into the respiratory tract or digestive system. Both of these usually end badly.

Diagnosis. The appearance of mites on the substrate and decorations. Especially they are clearly visible on dark objects (fig. 7).

Fig. 7. Mites in the chelicera area

Prevention. Maintaining the normal humidity and venting regime at the terrarium, removing the remains of food and excrements and substrate change if necessary. Do not use the ground, branches and snags from parks or forests.

Treatment. First of all provide dry quarantine with a drinker, if there are mites on the spider’s body. Remove the mites with either a dry brush (by shaking) or with a brush soaked in soapy water (1-2 drops of liquid soap per 0.5 liters of water). After that, very carefully "wash" the spider from the atomizer. If necessary, repeat these procedures. Wash all decorations in acetic water (1 liter of vinegar per 15 liters of water) and then pour them over with boiling water. The terrarium itself should be disinfected by maintaining dry quarantine for 1 month.

6  Flies from Phoridae family

Representatives of Phoridae family are relatively small insects 0.5 - 0.6 mm long, usually painted in black or yellowish. They are very similar to fruit flies, but do not like to fly, making double-quick rushes instead. These flies carry and transfer many infectious diseases, that is the main cause of their harmful effect on spiders. In addition, their larvae feed on living and dead flesh of arthropods.

Prevention. Maintaining of constant cleanliness at the terrarium. Flypaper should be hang in a room where spiders are kept.

Treatment. There are no effective treatment techniques.

7  Nematodes (roundworms)

This is a quite poorly studied disease, although the cases of tarantulas being infected with roundworms have increased significantly. There seem to be three main ways of infecting: the infection comes from poorly quarantined animals (caught from the wild); it can be transferred to the terrarium with water from open sources (wells, ponds, etc.); flies (Phoridae) can transfer nematodes’ eggs to the spider’s enclosure.

Diagnosis. Small white worms hang from the mouth area or just stay in it (fig. 8).

Fig. 8. Several nematodes in the chelicera area and near the oral cavity

 Prevention. Quarantine newly arrived animals in a separate room (dry quarantine with a drinker).

Treatment. First of all, fix the spider, clean the oral cavity from nematodes with eye tweezers, and then with a hard brush moistened in water (Bagaturov, 2001; Schultz, 2009; Marshall, 2001). Provide dry quarantine with a drinker and bottom in a clean box heated up to +32 - +35 °C for not more than 5 days. If necessary, repeat the procedure after 1-2 weeks.

8  Diskinetic syndrome

This is a very poorly studied disease, which has a lot of controversy and hypotheses. It is authentically known, that the causes of this syndrome can be as follows:

- bacterial infection;

- poisoning of food or substrate with pesticides;

- heavy metals and organochlorine compounds in water;

- protein intoxication (feeding tarantulas with rodents or frogs);

- fungal lesions;

- nematodes.

Diskinetic syndrome is the most dangerous disease and its treatment usually does not bring particular results. Conditionally, 3 stages of the disease are distinguished. The transition from the 1st stage to the 3rd can last from several hours to 5-6 months.


Stage 1: clumsy movements or limb twitching, when trying to run a spider raking up limbs for themselves (fig. 9), tree species can’t move on vertical surfaces. It lasts for 2-3 hours. There is a possibility of positive result if the treatment started in time.

Fig. 9. Symptoms of diskinetic syndrome in tarantulas (photo from www.tarantulas.ru)

Stage 2: flaccid reaction to irritants; the hind limbs rest against the substrate; abdomen raises above the usual position; the chelicera and fangs "plow" the substrate; limbs rake up for themselves; the defensive pose is taken clumsily; inaccurate attempts to hit the limbs for combing the protective hairs. This stage lasts from several minutes to several hours.

Stage 3: is a weak stirring and bending of limbs. Rapid lethal final follows ends this stage.

Prevention. Insects for feeding should not be taken from wild nature. Soil for houseplants should not be used as a substrate. Water for spiders should be stood or boiled prior to offering it to the tarantula.

Treatment. If the infection was caused by either fungi or roundworms see the corresponding section of the article. The remaining causes are fought as follows: separate empty container with a spider, provide complete dryness with temperatures of +30 - +31 °C with the help of underside heating. The spider is kept in such conditions during 3-5 hours. After that the temperature gradually decreases and the drinking bowl is offered. The sense is in making the spider defecating as much as possible. The number of sessions (min 4-5) for each species and age is different.

To sum up I’d like to add that in each individual case, as for treatment of any other diseases, it is possible to find any other measures, since it is better to try to find a way to cure the tarantula pet, even with a lethal end, than just sit calmly and watch the onset of its death.


The author would like to express his gratitude to Maksim Zadorozhnyi, Oksana Matsukevich and Natalia Ovcharenko for their support in preparation of this article.



1.. Bagaturov F. Spiders of the world and keeping of them in captivity. Illustrated atlas. – М., 2001. – 210 p. (in Russian)

2.. Stanley A. Schultz., Marguerite J. Schultz The Tarantula Keeper's Guide: Comprehensive Information on Care, Housing, and Feeding. – New Yorkꓽ Barron's Educational Series. – 3rd edition, 2009. – 384 p.

3.. Samuel D. Marshall Tarantulas and Other Arachnids: Everything About Selection, Care, Nutrition, Health, Breeding Behavior. – Malabar, Floridaꓽ Krieger Publishing Company, 2001. – 140 p.

4.. Michael Andreas Jacobi Animal Planet Pet Care Library. - New Jerseyꓽ TFH Publications Inc., 2011. – 112 p.