7 Terrarium Dangers for Reptiles


PetMD Editorial

Updated Aug. 16, 2022
Image: Elena P. / Shutterstock

Terrarium Tips

By Andrew Daniels

You’d never decorate your house with explosives, so why would you adorn your pet’s place with equally dangerous décor? Steer clear of these hazardous mistakes when you’re tending to your reptile’s terrarium.

Image: Heather Katsoulis / Flickr

1. Excessive Heat

While many pet reptiles require more heat than your home might provide, they can be susceptible to excessive heat, says Simon Starkey, BVSc, PhD, D.ABVP(Avian), Education Veterinarian and Technical Services Manage for PetSmart. To help curb the danger that too-hot temps may pose, place two thermometers in your pet’s habitat, Dr. Starkey suggests: one under the heat lamp—the hottest end of the habitat—and one at the other end. Adjust the bulb wattage up or down to meet your pet’s heat requirements, he recommends. Consult your veterinarian and check out resources such as PetSmart’s Care Guides to see the correct temperature and humidity ranges for your pet.

2. Hot Rocks

On the same token, hot rocks could put your reptile pal in serious danger. Although they aren’t nearly as popular as they used to be, these rocks are one way to provide supplemental heat in a habitat, Dr. Starkey says. Use them with caution. “Older heated rocks—or those from less reputable brands—can reach temperatures that may burn reptiles if they spend long periods of time sitting on the rock,” he says. This can be particularly problematic with snakes, which coil around the hot rocks and could receive serious burns. 

3. Lack of UV Bulbs

Most pet reptiles other than snakes and nocturnal lizards (like leopard geckos) require UVB light. “This allows them to complete the formation of active vitamin D within their skin,” says Dr. Starkey. Just like for you, vitamin D helps reptiles absorb and metabolize calcium, so they can have strong, healthy bones. But if you don’t put UV bulbs in your pet’s home, or replace them when the UV light burns out—often before the visible lights burn out—it can be life-threatening for reptiles, Dr. Starkey says.

4. Dirty Water

You can’t blame your pet for wanting to soak in its water bowl. After all, you do the same thing when you take a relaxing bath. But reptiles also tend to defecate in their water bowls, which can quickly lead to unsanitary conditions—as well as your pet not drinking as much water as it should, Dr. Starkey says. (Hey, you try guzzling down poop water!)


So you should regularly provide your pet with fresh, clean H2O—especially if you have a turtle. “Turtles spend most of their time immersed in water,” says Dr. Starkey. Make sure you read the manual that came with your tank: “It’s critical to use the right filtration system, to change the filters frequently, and clean the tank thoroughly as needed,” he says.

5. Incorrect Reptile Bedding

Different reptiles need different types of substrate, or bedding. (Check out PetSmart’s Care Guides to see the right kind of bed for your reptile.) For example, sand beds are harmful to insectivores like juvenile bearded dragons because they could ingest the sand along with their insect prey, says Dr. Starkey. 


You also want to avoid moisture-trapping bedding, such as Cypress bark, for desert species like bearded dragons. These bedding options retain unnaturally high levels of humidity compared to more appropriate bedding, says Dr. Starkey, and could cause give your pets pesky respiratory problems. 

6. Poisonous Plants

Poisonous plants (such as this Azalea, pictured above) are more likely to be a risk in larger outdoor tortoise habitats, Dr. Starkey says. But some poisonous plants could mistakenly find their way into an indoor reptile terrarium, and subsequently be eaten by an omnivorous or herbivorous reptile, he says. Double check this list of poisonous plants for reptiles to make sure one hasn’t landed in your pet’s tank. Fortunately, “there are very few reported cases of plant poisonings among reptiles” says Dr. Starkey. “Unfortunately there are even fewer studies of the relative toxicity of these plants to reptiles as compared to humans, cats, dogs, and rodents,” leaving some uncertainty as to which plants are poisonous for reptiles. It’s best to avoid all plants known to be toxic for other species, and consult a veterinarian about plants in your reptile’s environment.

Image: MichalV33 / Shutterstock

7. Live Prey Left in for Too Long

As surprising as it may seem, Dr. Starkey says, many reptiles are seriously injured each year by the live prey items fed to them. This usually occurs with rodents repeatedly biting snakes and causing severe wounds. That’s one of the reasons you should feed your pet snake frozen rodents that were humanely euthanized and now thawed, says Dr. Starkey. “Crickets have also been known to cause lesions to insectivorous reptiles—particularly to their eyes,” he says.