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Is my terrarium large enough? What size is best for your reptiles?

Is my terrarium large enough? What size is best for your reptiles?

How do I figure out what size enclosure is best for my pet reptile or amphibian

One of the best parts about keeping reptiles as pets is to see how unique they are in a captive environment. As a keeper, replicating their environment is essential, as well as providing adequate space for comfort and husbandry. Larger enclosures will help the keeper provide proper humidity/ temperature gradients, provide adequate space to move and explore, room to hide and feel secure. As reptiles became more popular in the 1980’s  the common standard for enclosures was mainly glass aquariums utilizing a screen top. The standard sizes range between 10 gallons to 75 gallons with top screen lid opening.  As our hobby evolved innovative companies such as Exo Terra ™ and ZooMed ™ designed front opening  enclosures for many different types of herps in mind. Many of these enclosures are designed for arboreal species. For larger reptiles, many companies have innovated larger, front opening, PVC or melamine large enclosures for popular animals such as Bearded Dragons and Ball Pythons. The standard glass enclosures aren't bad to use but they typically do not have enough width or base surface area for some reptiles.

Choosing your enclosure:

One of the most daunting questions that circulates our hobby is, What size enclosure is best for my pet? When doing your research on your new herp it is recommended to understand the full husbandry requirements of the animal. Then ask yourself once you decided on a tank size these following questions:

  1. Is it just enough space or more than we “need?” 
  2. What behaviors should I look  for if the enclosure is not large enough? 
  3. Will they need an upgrade in the future? 
  4. Will this be enough space to decorate and outfit with plants and the spaces to hide while not being overfilled? 
  5. Will the animal feel secure in this? 
  6. Can the herp get out?
  7. Is there space to put the necessary heating elements? Can this enclosure hold temperatures and humidity to allow the animal to thrive? 

If you can answer those questions after doing your research, then you are ready to move forward with your enclosure! 

Reptiles, amphibians and arachnids are cold-blooded that need heat or some sort of temperature control in captivity to maintain basic homeostasis. Each type of herp requires temperature and humidity very specific to them. When dealing with a larger enclosure heating and controlling humidity may be slightly easier to do because you have more space to work with. More space, means more heat dissipation and humidity dispersion. Reptiles such as Australian Frilled Dragons need basking spots upwards to 115-25 degrees. When dealing with such a high hotspot you need a very large enclosure to provide their essential thermogradient for proper heat regulation. In an enclosure too small, the keeper may have issues getting accurate temperature ranges which can cause health issues with your herps. It is imperative that as keepers we are providing our reptiles the best space for the temperature gradients. It is also important to keep in mind the height of your terrarium. The larger the terrarium the larger UVB bulb may be required to reach a higher Ferguson zone. 

In the wild, many types of reptiles will travel a large range to find food, shelter, territories and mates. While many are active nocturnally, or considered crepuscular, many diurnal species are known to use the daytime for basking or hunting. More species can be more sedentary than others, or some may require more height because they love to climb vs a terrestrial species that loves to run on the ground. A good rule of thumb is that a lizard that reaches 21-24” long (example: Bearded Dragon) should be given at least double the amount of space in length and at least 65% of that in width and height. This size enclosure would be a 4’ x 2’ x 2’ enclosure. Alternatively, if you have a crested gecko that reaches about 8” an 18” x 18”x 24” is a great starter size enclosure. The enclosures listed above are the minimum sizes for an adult, so if you wanted to offer something larger that provides a good framework to work up to. 

At the Bio Dude we love to preach the best care instead of the basic care. If customers ask us in store what size enclosure we recommend for an Adult Ball Python we will quickly recommend a 4’ x 2’ x 2’ PVC enclosure. While it is noted that they can survive and thrive in a 75 gallon many keepers report a much more active snake in a larger enclosure than the smaller. This principle can also be applied to many arboreal reptiles. With a larger floor plan or height it will also allow the keeper to provide more hiding spots, thermoregulation and humidity regulation opportunity zones, instinctual nourishment (the ability to provide live, edible plants or burrowing opportunities) for your herps. As mentioned earlier, providing them more space will allow them to act like wild animals. Many times you may see behaviors that you may have not noticed before. There will be many other benefits the keeper may notice which are listed below.

  1. Husbandry help - You will notice the temperature and humidity is easier to control. 
  2. Less impact from outside elements out of your control. Larger the enclosure = less chance of a hurt reptile in a glass tank if your AC goes out in the middle of summer. 
  3. More space provides breeding opportunities. 
  4. Higher standard of care which translates to a happier animal. 
  5. Different behaviors or territory displays may be noticed more frequently.  
  6. Providing a wild animal the space that they deserve. Reptiles and amphibians are much more intelligent than what keepers give them credit for. Many of them have very unique social hierarchies that will also come to life in a proper sized bioactive terrarium. 
  7. More space = more space for your reptiles to roam, keeper to provide different stimuli such as grasses, edibles or other means of enrichment. 

A myth hobbyists often hear is “reptiles grow to the size of their enclosure.” This is 100% entirely untrue and can lead to many health issues for your herps. An oversized turtle in a small enclosure will often have skin and bacterial shell issues. An adult Tegu in an enclosure too tiny will have a very hard time thermoregulating and could get upper respiratory infections. Even sedentary animals require a adequate amount of space. For example pacman frogs kept in too small of an enclosure have a high chance of developing severe fungal and bacterial infections. Sometimes, inadequate enclosures that filter out UVB may set your herps up for failure and lead them to developing Metabolic Bone Disease. MBD can be caused by a few things, the main two being inadequate UVB lighting and inadequate space. Making the bones become soft and depleting the available calcium sources, this cannot be reversed and can cause death. For this reason it's important that the animal not only have space to move and grow properly, but have the space on the top for the proper lighting required. 


The last thing to consider is the age of your inhabitant. There is a thing as too much space. While an adult leopard gecko can happily go in a 75 gallon sized enclosure, we do not recommend putting a neonate or young leopard gecko a 75 gallon until it is at least 6 months old as it can cause more stress than needed. Mainly, the smaller neonate can have issues finding prey, keeping hydrated and potentially feel stress from fear of predation from lack of security. While some may have success with keeping babies in larger enclosures, it should only be done by professionals with experience and know what to look for. Properly outfitted larger spaces can be utilized for smaller or younger reptiles, but if the reptile is smaller it is best to start with a smaller enclosure so they can acclimate easier. 

 As a whole the industry has come a long way to provide better husbandry in the way of commercially available enclosures.  ZooMed made ReptiBreeze for high airflow reptiles like Chameleons, ExoTerra designed enclosures that can be used for paludariums for many frog and salamander species and Kages PVC enclosures for terrestrial things like snakes or larger lizards. Regardless of what you decide for your reptile, security is key to keep the animal inside and feeling secure so they can thrive.  Not sure where do start with your reptiles enclosure or size? Reach out to us at or give us a call at 717 305 0684 for any additional help. 


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  • Josh Halter


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What a shame ----  you do not have permission to view this page : D