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Spindly Leg Syndrome: Reasons & Treatment

As someone who works as a zookeeper and is studying to be an exotic veterinary technician, amphibians diseases and ailments are a large concern and interest for me.

Learning the causes, signs, diagnosis, treatment, and prevention of exotic and wildlife diseases is important for all animals. 

Spindly Leg Syndrome is a a sickness in frog tadpoles affecting proper musculoskeletal function. SLS leads to underdeveloped limbs incapable of supporting the frog’s body once they are adult individuals. There is no treatment for SLS.

The current global amphibian decline has led to hand rearing of captive amphibian populations.

Hand rearing simply means raising populations or individuals in human care rather than in the wild, and these populations are the most affected by SLS.

Let me explain why, but first I’ll give more details on how we define SLS.

What is Spindly Leg Syndrome?

Spindly Leg Syndrome (SLS) is a sickness that affects captive anurans from a young age.

It is found to be related to captive reared populations and the conditions and environments they are kept in.

It affects the musculoskeletal aspects of an individual’s body. 

A frog with SLS next to a healthy individual (Lassiter, 2020)

If your frog has abnormal front legs, you may want to get it checked by an exotic veterinarian.

SLS leads to underdeveloped limbs that are not capable of supporting the frog’s body.

SLS leads to abnormal posturing and limbs, primarily front limbs. 

The joints tend to be malformed and muscle fibers of the limbs are reduced.

This leads to overall weakness in the body and can lead to death.

How do Frogs Get Spindly Leg Syndrome?

Spindly Leg Syndrome does not occur suddenly in adult frogs or toads.

It takes effect on the frog while they are in the aquatic larval stage of metamorphism.

That is, after they hatch from their eggs and before they venture onto land as froglets. 

The causes of SLS are nutritional and environmental.

It occurs in captive bred and reared anurans, typically species used as part of the pet trade.

Though it can affect those used for scientific or wildlife purposes as well. 

The reason it affects captive reared individuals is because of the artificial environments they are brought up in.

Type of water used, treatments or additives to the water, and nutritional aspect of the diet offered are large contributors to SLS. 

Soft tap water seems to rear high percentages of individuals exhibiting signs of SLS.

This is poor water quality for these populations that start life entirely aquatic. 

Tadpoles absorb nutrients and substances through their gills until they develop lungs, making them highly susceptible to their aquatic environment.

For example, they usually absorb environmental calcium through their gills into their bodies and store for later developmental use. 

But calcium may be lacking when bread in captivity.

Overfeeding and the overall nutritional aspect of the diet being offered to tadpoles also seems to affect their development of SLS. 

Overfeeding consists of offering too much food for the tadpoles to consume.

This leads to leftovers in the water.

These leftover food pieces break down in the water and change the chemistry and make up of the water the tadpoles are living in. 

There may be some filters to overcome this, but many times they just remove the larger debris and circulate the same water back to the tadpoles. 

The quality of the food being offered may be poor as well.

If it does not contain the proper nutrition balance for growing frogs, they could develop abnormally due to nutritional deficiencies. 

Is There a Treatment for Spindly Leg Syndrome?

If an individual shows signs of SLS, they have been affected by it since the tadpole stage of metamorphism.

There is no cure for SLS, and any treatments done may just stall the inevitable. 

A frog with SLS next to a healthy individual (Camperio, 2018)

Unaffected individuals may be fed supplemental calcium and nutritional, rotational diets to prevent metabolic diseases.

SLS is similar to metabolic bone disease in reptiles.

Treatment of MBD is typically using calcium and vitamins, though it will not get rid of the ailment. 

Unfortunately, there is no real treatment for reducing effects of spindly leg syndrome in frogs and toads. 

Humane euthanasia is the likely next step for severely affected frogs or those with a poor quality of life.

Now, those outside the animal care field may not be too familiar with the term “quality of life,” so let me break it down for you.  

An animal’s quality of life deals with their ability to eat, move, and really just survive.

I won’t say it evaluates their ability to “be happy” because it is difficult to tell how happy or sad an animal is just by looking at them. 

Same with pain (and frogs do feel pain).

It is difficult to assess the pain score of an animal that cannot talk and tell us.

However, there are some tell-tale signs.

  • If an animal stays in one space and will not move to water or food or burrow, there may be something wrong with it. 
  • If an animal refuses to eat, move, drink, or do normal frog behaviors, its quality of life is diminished.

Treatments may include pain management and assisted force feedings, but this will only prolong the inevitable outcome of humane euthanasia.

Euthanasia is humane when it allows the animal to pass peacefully instead of suddenly or painfully.

Of course, if you believe your pet frog is acting strange or exhibiting unusual behaviors, set up an appointment at an exotic veterinarian to have it evaluated. 

This article was written by Melissa M. who holds a Bachelors of Science in Fisheries and Wildlife Sciences, and a Master Herpetologist certificate. The article was edited and published by Daniella, Master Herpetologist in the author profile below.


Amphibian Rescue and Conservation Project. (2018, October 19). Retrieved from http://amphibianrescue.org/2018/10/19/spindly-leg-syndrome-in-amphibians/ 

Camperio Ciani JF, Guerrel J, Baitchman E, Diaz R, Evans M, Ibáñez R, et al. (2018) The relationship between spindly leg syndrome incidence and water composition, overfeeding, and diet in newly metamorphosed harlequin frogs (Atelopus spp.). PLoS ONE 13(10): e0204314. https://doi.org/10.1371/journal.pone.0204314 

Ciani, J. F. C., Guerrel, J., Baitchman, E., Diaz, R., Evans, M., Ibáñez, R., Ross, H., Klaphake, E., Nissen, B., Pessier, A. P., Power, M. L., Arlotta, C., Snellgrove, D., Wilson, B., & Gratwicke, B. (n.d.). The relationship between spindly leg syndrome incidence and water composition, overfeeding, and Diet in newly metamorphosed harlequin frogs (atelopus spp..). PLOS ONE. Retrieved from https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0204314 

Finding solutions for spindly leg syndrome in Amphibians. Morris Animal Foundation. (n.d.). Retrieved from https://www.morrisanimalfoundation.org/study/finding-solutions-spindly-leg-syndrome-amphibians

Lassiter, E., Garcés, O., Higgins, K., Baitchman, E., Evans, M., Guerrel, J., Klaphake, E., Snellgrove, D., Ibáñez, R., & Gratwicke, B. (2020, June 29). Spindly leg syndrome in atelopus varius is linked to environmental calcium and phosphate availability. PloS one. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7323948/

Daniella Master Herpetologist

Daniella is a Master Herpetologist and the founder of toadsnfrogs.com, a website dedicated to educating the general population on frogs by meeting them where they are in their online Google Search. Daniella is passionate about frogs and put her digital marketing skills and teaching experience to good use by creating these helpful resources to encourage better education, understanding, and care for frogs.