Anorexia in Reptiles - Causes, Prevention and Solutions

General Husbandry, Health Issues, Advanced Husbandry - Posted on 29 Jan 2015 by Andy


Anorexia is an all too common and frustrating problem encountered in reptile husbandry. Anorexia is a symptom, not a disease. Its treatment therefore depends on determining and correcting the underlying cause or causes. Anorexia can be triggered by a host of issues and it can be difficult to narrow down the problem, however 9 out of 10 times the cause is husbandry related and once identified, can be resolved easily. This is not to say that if you have a reptile that goes through a period of anorexia you are doing something intrinsically wrong! Animals are as individual as humans and while you may be keeping your particular pet in an environment that is deemed best for their species, your individual animal may require slightly different needs – such as more hiding places or different feeding routines.


Anorexia can be tentatively split into two separate classifications:

  • Anorexia that occurs in an animal that has never successfully fed

  • Anorexia in an animal that previously has been feeding well


Anorexia in a Previously Feeding Animal

Anorexia in an animal that was previously feeding can be incredibly frustrating. It is probably most common in new acquisitions, but can also occur in animals that appear to have been settled for a long period of time.

It can be all too tempting to fall into the (incorrect) assumption that a previously feeding animal suddenly becoming anorexic means that there must have been a change in circumstances to bring this about. It is true that more often than not this is the case, however, reptiles by their nature are extremely resilient and may tolerate certain stresses for long periods of time before they reach a “breaking point”. This can be seen in tortoises. Today, all the evidence points to tortoises kept in the UK needing a primary home indoors in a heated vivarium. But for many years tortoises were (and still are) kept in gardens in the UK. They will survive for many years in these conditions – some may even reach triple figures but the majority don’t; and those that do, tend to survive rather than thrive.

Key Issues:Temperature

  • Temperature related issues – often caused by drop/increase in temperature in non-thermostatically controlled vivaria as seasons change
  • Insecurity in environment – due to lack of hides
  • Over-Handling
  • Over Feeding


Anorexia in a Non-Feeding Reptile

Typically this type of anorexia is encountered in wild-caught animals but can also occur in new hatchlings/neonates that have been bred by yourself. In both cases, it is quite important to get on top of the issue as soon as possible, as these animals are typically more vulnerable and may not be able to weather long periods of anorexia as well as a previously-feeding and otherwise healthy animal.

Key Issues:

  • Incorrect Temperatures
  • Stress due to insecurity in environment – typically due to lack of hiding places
  • Parasites (wild caught)


General Recommendations

In an animal that is otherwise perfectly healthy and has been feeding prior to this episode of anorexia, you shouldn’t be immediately concerned. There are several reasons for anorexia that pose no direct risk to your animal such as seasonal (breeding) anorexia or simply not requiring food. Reptiles are extremely efficient animals and can go for surprisingly long periods without food - assuming they are otherwise perfectly healthy, and may resume eating of their own accord. The time to become concerned about an animal’s anorexia is if they begin to lose body condition or become lethargic, or develop other symptoms of illness. 

If your animal does develop anorexia, it is certainly worth making sure that your animal’s environment is correct and checking the potential causes below and addressing any issues you may find.

Baby miceIt is worth following a few sensible practices to keep stress levels in an anorexic animal to a minimum. While the animal is not feeding, stop handling all together – even if the animal is well handled and appears to tolerate it very well. Try and keep any unnecessary movement in and around the tank to a minimum and try and resist the urge to check on your animal too regularly – especially if it is new or wild caught.

When attempting feeding, it is often worth slightly reducing the size of the food offered, particularly if your animal has gone a long period of time without eating, or has regurgitated.

If your animal develops anorexia and shows other signs of illness (tremors, excess saliva, compaction etc.), or starts to rapidly lose weight, correcting the environment may not be enough and veterinary advice should be sought. 


Causes of Anorexia

Incorrect Temperatures

Spider-Man AgamaFrom our experience, issues with temperature are by far and away the most common cause for anorexia. Incorrect temperatures – whether too high or too low – can cause reptiles’ appetites to decrease for various reasons.

An enclosure that is too hot and has no areas for the animal to escape the heat and cool down will often result in anorexia as well as a host of other problems. An animal subjected to overheating will often be incredibly stressed, sometimes aggressive, and feeding will become a lower priority than escaping the heat.

When the enclosure is too cool, reptile appetites become suppressed. Being cold blooded, reptiles take heat from the environment to warm their bodies and need to reach specific body temperatures to function properly. Enzymes and digestive bacteria in reptiles’ digestive tracts will not function effectively when the animal’s body is not at an optimum temperature. Therefore, even if food is consumed, it will not be digested effectively. This can cause various problems such as compaction, gastrointestinal diseases and the animal will not absorb nutrients as effectively from their food. Often, reptiles subjected to lower than optimum temperatures will reduce their appetites so that they do not “overload” their digestive systems, or may stop eating all together. 

Habistat dimming thermostatReptiles need to be able to “thermoregulate” (maintain a stable body temperature), and to do this it is vital that their enclosure provides a thermal gradient i.e. a hot and cool end. Achieving this is simple; all heat sources should be placed down one end of the tank, leaving the other end free of heat sources to produce a cool end. Different species have different temperature requirements, so make sure that you know what your animal’s optimal temperature is. We measure the ambient temperature in the middle of the enclosure to determine the most effective temperatures for different species. The temperatures found at the hot and cool ends are typically inconsequential so long as the ambient temperature is correct. (This may not be the case with certain species which require very high basking temperatures such as Uromastyx species and Dwarf Spiny Tailed monitors etc.).

The most reliable way to achieve the optimum temperature for your animal is through the use of a thermostat. A thermostat simply connects between your heat source and the mains power supply and regulates the power sent to the heat source based on the temperature in the tank – measured by the temperature probe. Various types of thermostats are available and some of the more advanced thermostats can set day/night temperature settings and control UVB lighting on a day/night on/off cycle.

Suggested Ambient Teperatures of Common Species:

  • Bearded Dragon – 84F
  • Leopard Gecko – 82-84F
  • Water Dragon – 84F
  • Corn Snake – 82-84F
  • Hognose Snake – 84F
  • Hermann’s and Horsfield's Tortoises – 82F
  • Leopard Tortoise – 84F
  • Crested Gecko - 78F
  • USA Green/Grey Tree Frog - 76F

Night-time drops in temperature are a common suggestion found online on websites and forums among other places. We have found that only a select few species seem to benefit from night time drops and  in most cases, night-time drops in temperature generally cause more problems (including anorexia) than benefits. But if you are set on providing a night time drop for your animal other aspects of the animal’s husbandry must also be adapted to account for these drops in temperature – one of which is feeding routine. For advice on how to best adapt your animal’s husbandry to account for a night time drop or to find out if your species benefits, give us a call.


Enclosure Security

Probably the second most common cause of anorexia is due to anxiety, caused by the animal’s insecurity in its environment. If an animal does not feel safe in its environment then it simply won’t be interested in feeding. Recently wild caught animals are most susceptible to this issue which is why we do not sell any wild caught animals that are not already fit, healthy, feeding and well settled. Some species tend to suffer more, with a condition called “maladaptation syndrome” where individuals simply do not adjust well to captivity. For this very reason we are careful with the species that we import and only import those that in our experience adapt well. 

Long term captive animals as well as captive bred animals can also feel unsafe in their environment and therefore risk becoming anorexic. This is most likely to occur after a move to a new environment such as when bringing a new animal home but can also occur if an enclosure’s position in the house changes.

To help an animal feel safe and secure in its environment it is important to provide it with plenty of hiding places. When it comes to hiding places, Less is…simply Less. It may seem like backwards logic, but placing an excess of hiding places in your animal’s environment is likely to result in you seeing more of your animal out and about behaving naturally. If you place just a single hiding place for your animal, you can bet that they will spend the majority of their life under it, too scared to venture out.

As important as the quantity of hiding places is also the shape and size of them. Placing a hiding place that is far too big for your animal will provide little or no benefit to it. In particular, royal pythons love hiding places that they can only just squeeze into. As far as they are concerned, if they can only just fit into the space, no predator can reach them and they feel safer.

If you have an animal that has stopped feeding it is always worth placing a few extra hiding places in its enclosure or adding foliage and tank décor to break up large open spaces.


Food Source / Feeding Routine

Anorexia can be brought on by offering a food type that your animal is not keen to eat. In snakes this may be size related. Snakes will sometimes refuse to eat a mouse/rat that is too small for them and will often refuse food that is too large. Occasionally, a snake may start refusing to eat a certain food type, be it mouse or rat. Switching temporarily, from a mouse to an equivalent sized rat, or vice versa, can encourage a snake to eat and kick-start its digestive system again, meaning it is more keen to feed in future and you should be able to switch back to the original food source after a few successful feeds. 

Fruit Beetle GrubIn a similar way to snakes, lizards may occasionally get “bored” of a food source if they are only fed one type. Variety is important but should be provided by using a different food source on separate feeds and not by feeding your animal a load of different insects at one time. When using mealworms or waxworms in a dish, sometimes visibility can be an issue and it can help to inset the bowl into the substrate to help make it easier for your animal to see and get to the insects.

Some reptiles are nocturnal, such as crested geckos and leopard geckos and feeding them during the daytime may be less successful than feeding them at night when they are more likely to be out and about and looking for food.

Mealworms in a bowlLeopard geckos can suffer from a unique problem that can arise if mealworms are not provided for them to eat. Many Leopard geckos are captive bred in large numbers on the continent and they are primarily fed on mealworms. If mealworms are suddenly removed from their diet, they can go through what appears to be a kind of mealworm withdrawal. They may rapidly lose weight and refuse to eat. For this reason we always recommend providing leopard geckos with a bowl of mealworms 3-4 days a week.


Overfeeding (Food Blindness)

Bearded dragon locustThis is separate from the issue of obesity but may be linked. This cause of anorexia is a little unusual and is only relevant to an animal that has previously been eating well. When provided with an over-abundance of food many reptiles (particularly lizards and amphibians) will stop feeding. The specific reasons behind this are unknown but are believed to be due to one of two things: The animal realises that there is an over-abundance of food and therefore feels under no pressure to make any particular effort to eat, as there is no urgency to find food; This lack of urgency if prolonged may eventually start to suppress appetite as the digestive system slows down. OR, the constant movement of food in the enclosure desensitises the animal, which no longer sees the food as prey but instead sees it as simply part of the environment.

If this is the cause of your animal’s anorexia then it is typically easy to resolve. Simply remove any food from your animal’s environment and leave them without any food for 2-3 days (assuming they are otherwise healthy). After this “fasting” period reintroduce a small amount of food and see if they eat. If not, go through another 3 days of fasting and try again. Chances are that by this point, your animal will be hungry and will jump at the chance to eat any food provided for it. If even after this period of fasting your animal still refuses food, it may be worth considering that there may be another reason for its anorexia.

WaxwormsAs mentioned in the Feeding Routine section above, it may be helpful to initially try an alternate food source after the fasting period. For example, if your animal has been primarily fed on locust or crickets, try an insect that doesn’t hop around, such as cockroaches, mealworms, wax worms or fruit beetle larvae. With non-jumping insects, like those mentioned above, it is best to provide them for your animal in a bowl, shallow enough for your animal to easily see into, but not so shallow that the food can escape.


Competition/ Bullying

This issue is only relevant if you have more than one animal in the same enclosure. Housing certain reptiles together can often be achieved relatively risk free if you follow good practices. See our other blog post on housing reptiles together for more info.

Bearded dragon dominancyWhen two animals are housed together, while they may appear to “get along” they will see each other as competition for space and for food. In some circumstances this can result in physical and psychological bullying. Whilst the former is usually pretty obvious, psychological bullying may not be and it can be a cause of anorexia. There will always be one animal more dominant than the other, and the dominant animal may only allow the subordinate animal to feed once it has eaten its fill, or may even pressure the subordinate animal into refusing to eat all together.

The simplest and most effective way of solving this problem is to separate the animals. Other ways of tackling this problem should only be seen as temporary as they will simply gloss over the problem and mask it – the stress of being housed with an overly dominant animal will still be present and the issue of anorexia may return. That being said separating the animals during feeding is a potential way of managing this issue. It is usually best to remove the dominant animal leaving the non-feeding individual in the enclosure, though if this doesn’t work after several attempts it is worth attempting it the opposite way round. 


Seasonal Anorexia

This is most common in male individuals – especially male Royal Pythons. During the breeding season many animals will reduce their appetites and may even stop feeding all together. Male royal pythons have been known to go several months or more without eating during this time. Even though you may not set seasonal temperature and lighting changes in your animal’s enclosure, they may still pick up on these changes from the external environment. Flat-tailed horned lizards (Phrynosoma mcallii) have been shown to undergo brumation in the autumn regardless of the temperature that they are kept in captivity.

So long as your animal is otherwise fit and healthy and is not losing weight, inappetance during breeding season should not give you cause for concern. However you should make sure there are no other potential causes for the anorexia and keep a close eye on your animal’s physical condition.

AutumnTowards the tail-end of summer and the beginning of autumn, animals may pick up on the shorter days and cooler air temperature outside their tanks. This may cause them to prepare for winter and brumation, during which time their appetites would normally decrease. If your tank is thermostatically controlled and the ambient air temperature inside the tank remains stable, your animal should eventually snap out of it and realise they do not need to go through brumation and feeding should resume. If your tank temperatures are not controlled by a thermostat then you need to find a way of maintaining a suitable stable air temperature such as by changing the wattage of bulb used to heat your enclosure. For lizards, temporarily increasing the amount of time the UVB light is on for by an extra hour may also help them to snap out of preparing for brumation.


Handling and Over-Handling

One of the first things to change when an animal stops eating is handing. Handling can be a stressful experience for an animal, especially in a new acquisition which may not have settled in properly yet. This is why we always recommend leaving your animal at least 4 weeks before you begin handling, to allow it to settle in and so you can make sure it is feeding well and behaving naturally. If your animal stops eating, simply stop all unnecessary handling and wait until it is back to eating consistently.


Other Issues that May Cause Anorexia

  • Dehydration – primarily in newly acquired animals – especially wc!
  • A Lack of Necessary Special equipment – e.g. retes stacks (dwarf ackies/ monitors), branches (arboreal lizards and snakes)
  • External environmental factors – noise, aerosols
  • Humidity


Physiological Causes

Physiological causes are likely to require veterinary advice and treatment to properly resolve them. So if you suspect any of the following to be the cause of anorexia we strongly recommend that you seek out a good veterinarian with reptile experience.


Mites are a reptile keeper’s nightmare. They are extremely resilient, reproduce rapidly and can cause all sorts of problems if they are not dealt with swiftly and effectively. Whilst most common in snakes, mites can affect lizards, particularly lizards with rough scales. Mites are extremely irritating for the affected animal and can often suppress the animal’s desire to eat. The most effective way of eliminating mites is to see a veterinarian and get an injectable treatment – though some species react badly and can’t have this. Additionally, the enclosure should have all of the substrate and décor removed, the substrate should be discarded and replaced with newspaper and décor should be thoroughly cleaned, preferably with boiling water. The enclosure should then be thoroughly cleaned with hot water and a retile safe disinfectant. After a few weeks, once it appears all the mites have been eliminated, substrate and décor can be replaced.

Other Parasites

Other parasites can be found in captive bred animals, but are most common in wild caught animals. Other parasites - especially intestinal parasites such as worms, can really have an impact on an animal’s desire to eat. Intestinal parasites can be hard to detect, but you may see evidence in the faeces with the presence of eggs. Occasionally the stomach will bloat due to parasites, but the only way to really check for parasites is to send a faecal sample off for analysis - most vets should be able to offer this.



Compaction is a condition where an animal’s gut becomes blocked, either by urates, ingested substrate, faeces or another blockage – resulting in an inability or a limited ability to pass waste. When an animal becomes compacted, their first instinct can be to stop feeding so as not to make the issue worse. Compaction can – but not always be spotted by noticing a bulge at your animal’s rear and/or by repeated and sustained failed attempts at passing waste. Sometimes compaction can be resolved in the early stages by giving your animal a bath in some lukewarm water for around half an hour. If this doesn’t resolve the issue, veterinary treatment should be sought. 

Metabolic Bone Disease (MBD)

MBD is the name given to a group of conditions whereby the bone structure of the animal is weakened. For more info specifically regarding MBD, read our MBD article here. MBD can cause the jaw bones to weaken, resulting in a soft jaw which can make feeding difficult and sometimes painful. If you suspect MBD to be the cause of your animal’s anorexia, it is important that you seek veterinary help as soon as possible.

Other Illnesses

If your animal is feeling under the weather due to other illnesses such as respiratory infection, stomatitis or gastroenteritis - this too could cause anorexia. Look for signs and symptoms of these and other possible illnesses to check that a separate illness isn’t causing anorexia.


Words of Warning

Assist/ Force Feeding

Force feedingAs a general rule, we never attempt to assist feed or force feed any animal, and we recommend that you do not attempt it either. 90% of the time, an anorexic animal can be persuaded to feed without the need for assist/ force feeding and oftentimes, attempting this can cause more harm than good – especially if you do not have extensive experience in performing it. Assist/ force feeding is a very stressful process for the animal and the stress can be just as detrimental to the animal as the anorexia itself. This stress can have a negative impact on the effectiveness of the animal’s digestive processes and will reduce the benefit of any meal received and increases the likelihood of regurgitation. It may also result in the animal never fully regaining its feeding response.

There may be unusual and rare situations where force feeding is the only/ best option. If you think your animal may be in this position, please give us a call or speak to a reputable reptile vet or pet shop for advice.


Feeding Chick/ Hamster

ChickIn some circumstances, as mentioned in a previous section, changing the food source can help an animal regain its feeding response. With particular regard to snakes, switching from rodents to chick or hamster can work well. We’ve found Burmese pythons are particularly keen to feed on chick. However, both chick and hamster can be somewhat addictive and should be avoided if possible.

Nutritionally chicks are a poor food source long term for snakes and hamsters can be hard to get a hold of and are also much more expensive than the equivalent rat. A better option can be to use a chick to scent a mouse or rat to tempt a snake into eating. Combining this scenting technique, with periods of fasting before attempting unscented food can work very well in encouraging a non-feeding snake into eating its normal food source again.


Non-Vet Treatment


The benefits of the use of Powerade are mostly anecdotal but its use is often recommended on forums and other places online. Powerade is used to help treat anorexia by preparing a 50:50 solution with lukewarm water and bathing your animal in the solution for around 30mins. With a bit of luck your animal will have a drink of the diluted Powerade, which is full of electrolytes and sugars which can help to boost an animal’s digestive system and increase its appetite.


Gut flora enhancers

Verm-X for ReptilesIf you have an animal that has recently regurgitated - whether or not it is otherwise feeding well, it is worth thinking about purchasing one of the several supplements available that help boost the good gut flora which help your animal digest food (such as Verm-X). After an animal regurgitates, a large amount of their gut flora are also removed which makes digesting food harder. The gut flora will gradually recover on their own, but these supplements can help promote their recovery.  The supplements are usually in powder form and can be dusted onto rodents or insects. Just remember to reduce the size of the meal you provide for a period, until your animal has gone several weeks without regurgitation.

This is by no means a comprehensive article on Anorexia and if you are unsure about any of the above and your animal isn’t feeding properly feel free to give us a call or pop in and see us at the Southbourne store and we’d be happy to talk through things with you and help you get your animal feeding well again.

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