Reptile and Amphibian Nutrition

Tortoise eating hay Resa McLellan


Nutrition is the leading cause of disease in reptiles and amphibians. Chronic nutritional diseases remain common, including nutritional secondary hyperparathyroidism, hepatic lipidosis, protein deficiency, hypovitaminosis A, hypervitaminosis A, pyramidal shell growth, renal disease, urocystoliths, thiamine deficiency, vitamin E/selenium deficiency, steatitis, corneal lipidosis, and obesity. The goal of this lecture is to educate veterinary health professional such that they can provide sound nutritional advice to reptile and amphibian keepers.

This lecture was adapted from Boyer, TH, Scott, PW. Nutrition. In: Diver S, Stahl, S (eds). Mader’s Reptile and Amphibian Medicine and Surgery, 3rd ed. St. Louis, MO: Elsevier; 2016:201-223.



Photo:  Dr. Lauren Thielen


green tree frog Litoria

Photo: Stephen Michael Barnett via Flickr Creative Commons

  1. Water
  2. Nutritional biology
  3. Herbivores
    1. Salad type diets
    2. Grasses/hays
    3. Complete manufactured diet
    4. Misconceptions
  4. Insectivores
    1. Calcium
    2. Dusting
    3. Gut loading
    4. Variety
  5. Carnivores
    1. Snakes
    2. Piscivores
  6. Omnivores
    1. Box turtles
    2. Aquatic turtles
    3. Bearded dragons
  7. Conclusions



About the presenter

Thomas Boyer earned his Doctorate of Veterinary Medicine from Colorado State University College of Veterinary Medicine in 1989. Dr. Boyer co-founded the Association of Reptilian and Amphibian Veterinarians in 1991 and he started and served as editor for the Journal of Herpetological Medicine and Surgery for 18 years. Dr. Boyer also helped establish and became one of the first Diplomates of the American Board of Veterinary Practitioners in Reptile and Amphibian Practice in 2011. Dr. Boyer owns the Pet Hospital of Penasquitos in San Diego, California, where he treats a diverse reptile caseload. [MORE]


Webinar recording


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Expert Q+A

Although many questions were answered verbally during the live event, most remaining answers were typed by Dr. Boyer before he exited the webinar “room” and are posted below. Three additional questions were later submitted by an attendee that listened by phone.


I had a lot of confusion about the vitamin A in tortoises. First you said do not give injectable vitamin A for hypovitaminosis, then you said to do it once at 5000IU once (repeat in a few weeks if needed), then you said do not give oral vitamin A… Is this true for vit ADE too? I have successfully treated hypovitaminosis A multiple times in tortoises by giving them vitamin ADE once if severe and NPO, then repeating in 3-4 weeks if needed.

Do not give vitamin A injections to tortoises (Testudinidae), being herbivores they seem good at converting carotenoids to vitamin A and do not get vitamin A deficiencies, although they were widely given vitamin A injections in the past.

Emydidae turtles (box turtles, sliders, terrapins, pond turtles), being more carnivorous, do seem prone to vitamin A deficiency, and can be given vitamin if symptomatic (eyelids swollen shut). We use ADE, at 5,000 U/kg, repeat in 2 weeks.

How would you introduce proper diet to a chelonian not eating hay?

Mix into salads, be persistent

Can you still add hay to a Testudo horsfieldii‘s diet even though they are more browsers than grazers?


What do you recommend be added in to a gopher tortoise rehab diet? Currently doing romaine, green leaf, veggies and small amount fruit. Topped with Mazuri pellet and calcium with an without D3 depending on the day.

More commercial pellets and hay, less fruits



Phoenix worms/ black soldier fly larvae (BSFL) are often sold as not needing to be fed at all, thoughts?

Starved insects [are] never as good as gut-loaded insects, having said that [I] don’t have experience gut loading SFL.

Where can I find works cited about wild caught insects not causing parasitism?

I do not have references citing wild caught insects do not transmit parasites.



Do you recommend calcium gluconate versus carbonate for oral supplementation?

We switched to calcium carbonate when calcium glubionate became commercially unavailable.

You said that you use 0.25 mL calcium carbonate per kg. What is the strength of this formulation (mg/ml)?

250 mg/ml, through Wedgewood

What is your opinion on Arcadia Earth Pro Supplements?

Not sure, check the labels

Just checking supplementation recommendations:  (a) feed bugs gut load all the time and it won’t kill themselves long as they have water access (b) dust with calcium only every feeding (c) use multivitamin 1 or 2 times a month ….Correct ?

Yes, plus wide variety of insects



In snakes, I get asked a lot about anorexia for several months. Is there any new studies about average length that is normal for snakes to be inappetent during brumation times? When (days/weeks/months) should we be concerned the inappetence be concerning?

Most snakes hibernate 3-4 months, starting in September/October/November and emerging once warmed in the spring March/April. Ball pythons do not hibernate but often go off feed for 5 months in the winter.



Doesn’t fish contain thiaminase (or maybe not all fish?) and feeding raw fish to reptile can cause hypovitaminosis B1?

Some fish do, less in the species I mentioned.

And is there a risk of parasites with feeding raw fish or does freezing kills the parasites?

Freezing for 3 days kills pentastomids

Have you ever seen beriberi (thiamin deficiency) in aquatic turtle fed too many minnows and goldfish?

No, but reported in garter snakes.

Editor’s note: See “Thiamine (Vitamin B1) Deficiency in Garter Snakes” by Sean McCormack BSc for additional information.

I’m hung up on…the cause of steatitis in piscivores. I know one of the causes is rancid fish…

Steatitis, fat inflammation and necrosis associated with fish high in polyunsaturated fatty acids, or rancid fat, or low in tocopherols or selenium.



Would you add small amounts of chopped hay to a bearded dragon diet for additional fiber?

Beardies are more browsers then grazers



Is it safe to surgically remove fat pads in [bearded dragons] if you need to, like if they tear or are in the way?



RACE approval

This program is approved for 1 hour of continuing education by the American Association of Veterinary State Boards Registry of Approved Continuing Education for veterinarians and veterinary technicians.




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To cite this page:

Boyer TH. Reptile and amphibian nutrition. LafeberVet web site. Nov 2, 2021. Available at