Home | Frank's Creatures | My Animal Collection: How a Herpetologist Keeps Barking Treefrogs (Hyla gratiosa) and Gray Treefrogs (Hyla versicolor)

My Animal Collection: How a Herpetologist Keeps Barking Treefrogs (Hyla gratiosa) and Gray Treefrogs (Hyla versicolor)

Today I would like to offer a look at how I set up a terrarium for animals in my own collection. After decades keeping animals privately and professionally, my techniques have become a fusion of tried and true methods and ideas that I have either worked out or (often!) stumbled across. Of primary importance has been the writings and personal advice of many kind and dedicated people.

Wonderful but Neglected Terrarium Pets
Frogs in My Battery Jar Terrarium I’ve never quite understood why barking and gray treefrogs have remained largely ignored by herptoculturists. Both are beautifully patterned – the gray frog subtly, the barker often quite brilliantly – and almost always make themselves right at home in captivity. Wild caught adults of either species have hand-fed for me as soon as 1 week after capture, and a gray treefrog that I have now approaches the glass when I enter the room, in a much more “turtle” than “frog-like fashion”. At nearly 3 inches in length (and appearing larger due to its stocky frame), the barker is the USA’s largest native treefrog, exceeded only slightly in size by the introduced Cuban treefrog (Osteopilus septentrionalis).

Setting Up a Battery Jar Terrarium
I currently keep 1 barking and 1 gray treefrog in a battery jar terrarium of about 10 gallon capacity. I favor battery jars for the simple reason that they were always mentioned in the naturalist/pet-keeping books of yesteryear. As a child, I had no idea what a battery jar was, but imagined it to be a fabulously exotic item, the possession of which would confer instant “professional animal-keeper” status upon me.

In reality, battery jars are thick-walled, usually cylindrical glass containers available from biological/laboratory supply houses. Their vertical orientation serves arboreal frogs well, but a 20 gallon “extra-hi” aquarium or larger plastic terrarium is also perfectly suitable.

My battery jar was modified for use as a terrarium by Bob Holland, a friend who was well-known in the 60’s and 70’s for his success in keeping – years ahead of most public collections – poison frogs, banded tree snails, woodland salamanders, mosses, ferns and a host of other delicate organisms.

Bob used aquarium silicone and a piece of glass to create a small pool and to attach a hollow piece of lava rock about ½ way up one side of the terrarium. The lava rock functions as a planter, and the area below as secure shelter…the treefrogs rarely use it, but in earlier times it was favored by a marbled salamander (Ambystoma opacum).

My skillful friend cut a ventilation panel into the terrarium’s glass top, a task I would not attempt. Commercial glass cutters can do this for you if you are as “tool-challenged” as I, after which you can silicone a piece of fine screening in place.

The substrate is Eco earth loose coconut with a bit of sphagnum moss mixed in. A layer of aquarium gravel and activated carbon, situated below the substrate, assists in drainage and ammonia absorption. I use live, locally collected moss on top of the substrate – you’ll need to experiment with the moss species, but many do well with moderate lighting and daily misting. Compressed frog moss works well to fill in dark corners, or as a substrate for the entire tank if you prefer.

Live Plants, Light and Decorations
I chose the live plants for this terrarium based upon their serviceability as frog perches and modest light requirements. The aptly-named cast iron plant (Aspidistra elatior) is nearly indestructible, and is often used as a perching site. The Chinese evergreen (Aglaonema modesta), snake plant (Sansiveria spp., not pictured) and earth star (Cryptanthus spp.) are equally hardy. Earth stars are a favorite of tarantula-keepers, as they get by on very little light (they turn brown at such times, but return to red when moved to a brighter location).

A Reptisun 2.0 florescent bulb provides sufficient light for the plants without exposing the frogs to harmful levels of UVB – most amphibians have UVB “filters” in their skin, and actively avoid the sun.

A Caution Concerning Light
Another Frog Terrarium ShotI have noticed corneal opacities in green and gray treefrogs that consistently perch directly below even low-level UVB output bulbs. To be on the safe side, keep track of your frogs’ perching habits. Most tend to choose the same spot day after day, and it is usually an easy matter to fashion a shield (i.e. an artificial plant) between the frog and the bulb.

A few attractively-weathered pieces of driftwood provide additional climbing surfaces. Exo terra terrarium plants are extremely life-like, more so when integrated among living plants. I find them especially useful in creating exhibits in zoos and museums, where the plant species used must match those found in the subject animal’s habitat, or where light levels limit the use of live plants.

One drawback of a battery jar terrarium is the relatively small area that can be vented. In the summer, temperatures within may become too warm for most amphibians, if even a florescent light is used. The aforementioned plants will usually survive on room light alone for a few months – to be safe, I set the terrarium light to go on for 2-3 hours during the cool of morning.

Plants as Waste Managers
I always fear downplaying the importance of regular cleaning, and it is not my intention to do that here. However, well-planted terrariums that are lightly stocked with animals are a delight to maintain.

The key is to have enough plants with vigorous root systems, live moss if possible and to find the right balance of plants and animals. The tank pictured here would actually be more easily maintained with just 2 gray treefrogs, or a single barking treefrog, as opposed to 1 of each, but I am familiar with its capabilities, and monitor it carefully. This terrarium has been up and running, with only two major substrate changes (one after housing a sick animal), for nearly 12 years.

Help From Snails and Sowbugs
In addition to the plants, I am assisted in tank maintenance by a thriving colony of land snails and sowbugs (Check Out: Terrestrial Isopods as Food for Captive Reptiles and Amphibians ). Both avidly consume the frogs’ waste products and decaying plant material, and neither requires additional food. The sowbugs provide an alternative food source for the frogs as well. I spot clean when necessary, occasionally replace the top inch of substrate, and change the pool’s water by wicking it out with paper towels. A layer of activated carbon below the substrate (an old trick now largely forgotten) helps to absorb nitrogenous wastes.

Feeding Native Treefrogs
Wild Caught Insects
Frog swallowing a hand-fed cricketMy gray treefrog hatched in captivity, and the barker acts as though it did – both feed avidly from the hand. This allows me to more easily provide a varied diet, as they will take canned insects such as caterpillars and grasshoppers. From spring through fall, I feed the frogs exclusively upon insects that I trap with a Zoo Med Bug Napper or collect around my outdoor yard light. An insect or 2 each day or so suffices, and the dietary variety is key to good health (Check Out: Providing a Balanced Diet to Reptiles and Amphibians).

This is just a thought, but I believe it cannot hurt to attempt to provide arboreal and flying insects to tree frogs – especially so if you live within the range of the frogs that you keep. Mine favor moths, tree crickets, small katydids, caterpillars, beetles, harvestman (“daddy longlegs”) and flies. I avoid spiders, fireflies, ladybugs and brightly colored species, due to possible toxicity problems, and do not collect for a week or so after the area has been sprayed to control West Nile virus ( I believe the plane-sprayed insecticides kill far more cicadas than mosquitoes, but I digress…).

Commercially Available Insects
During the winter, temperatures in the terrarium average 62-65 F, the light cycle is reduced to 8 hours, and the frogs slow down. A once-weekly feeding of crickets (use only small ones for gray treefrogs), mealworm beetles, waxworms and earthworms holds them until tastier meals return (most treefrogs refuse earthworms, but some individuals will accept them).

I powder feeder insects with a vitamin/mineral supplement during the winter only – I’ve found such is unnecessary in summer, when wild caught insects dominate the diet.

The frogs and terrarium are sprayed once or twice daily with de-chlorinated water (both species use the pool as well).

There are 2 nearly identical species of gray treefrog in the Eastern USA. You can learn how to distinguish them, and a bit about the National Wildlife Federation’s laudable Frogwatch USA Program, at:


  1. avatar

    Im not sure this gets to Frank but if it does,,, boy best friends throughout grammar school, you moved and here I stumble on you over the internet.. Got your curiosity, write back. Read your biography, I remember you getting that turtle and I also had to be bored to death every week watching animal video’s in your house. hahaha

  2. avatar

    How do you control fungal problems in the live plant habitats? Also, how do you suggest mounting a light for the plants above the battery jar?

    _Jen Reptiles Alive Blog

  3. avatar


    Frank Indiviglio here. Thanks very much for your interest and comment.

    I haven’t experienced any problems with fungal growth in this or similar terrariums. The ventilated panel in the glass lid seems to provide sufficient air circulation, and the plants and frogs require only a light misting… the frogs soak in the pool nightly, which meets most of their needs. Mold will occasionally appear on the live moss – I remove the moss in that area as soon as I note this…the moss re-grows rapidly.

    I’ve noticed that terrariums vary greatly as regards mold and fungus – even if set up identically, each will have its own particular ecology. Often a change in the location of the florescent bulb, or in the length of the light cycle, or in the amount of ventilation, will help eliminate fungus and mold. This is easy with grey and barking treefrogs, as both dry out considerably each day in the wild…a bit more difficult with poison frogs and some others.

    Where this is insufficient, you can try watering plants by sinking a hollow glass or plastic tube into the soil and adding water through it…this will wet the roots but allow you to control surface moisture (credit for this goes to Dick Bartlett, not I). This technique is very useful for desert/arid terrariums, and for keeping spadefoot toads and other fossorial species that prefer a moist bottom soil layer and dry substrate on top.

    To light the terrarium, I merely rest a small reflector on top of the terrarium, over the ventilated area. The bulb is a low watt florescent, and so heat buildup is only a problem in mid-summer. At that time I cut back on use of the light, turning it on in the early morning and evening only. The plants I use are all quite tolerant of this… earth stars turn brown, but return to their usual red shortly after the light cycle is increased. Alternatives might be an adjustable desk lamp or a wall-mounted unit.

    I hope this was helpful…let me know if you need further information, and please pass along your thoughts and observations. Best regards, Frank Indiviglio.

  4. avatar

    I got a question about mixing frogs and toads…
    I currently have 2 squirrels and 2 grey tree frogs housed in 20 gallon..

    I found 2 tiny toads which got injured by lawn mower a couple weeks ago and have thoughts of keeping them and placing them in 20 gallon with other frogs…Can I mix them…..These frogs and toads are all about the same size.

    I am checking temperature and humidity levels to see if they are compatable…..

    Any ideas would be great…
    They sure are cute.


    • avatar

      Hello, Frank Indiviglio here.

      Thanks for your interest in our blog.

      Depending upon where you live, the toads are most likely American, southern, Fowler’s or other closely related species within the genus Bufo (recently re-classified as Anaxyrus). The care of all is similar, and, technically, they will co-exist with squirrel and gray treefrogs. They feed upon the same foods and do well at the same temperatures and humidity levels.

      However, toads are, in general, far bolder than treefrogs. They make great pets and will soon by hopping about in anticipation of a meal when you approach. They become very tame are always hungry, and therein lies the problem. The toads will usually consume all the insects placed in the aquarium before the treefrogs even know its feeding time. This is especially true if, as is usually the case, the treefrogs wait until dark to feed.

      I have kept treefrogs and toads together, but it takes a good deal of management. If your treefrogs feed right away, it might work out. Or you might try feeding the toads in the day and adding additional insects at night…but again keep an eye on them, as the toads will feed at night as well as by day.

      Good luck and please keep me posted.

      Best regards, Frank Indiviglio.

  5. avatar

    I have been keeping Green Anoles for about a year now. I came across the Barking Tree frog and thought it would be cool to house them in a multi-species terrarium with my Green Anoles. What are your thoughts on this? What problems should I keep an eye out for? What would be a good substrate for both species?

    • avatar

      Hello Jennifer, Frank Indiviglio here.

      Interesting idea, thanks for writing.

      I have kept barking tree frogs and green frogs with anoles in zoo exhibits, and it works out quite well. Their ranges overlap in the wild and they do well at roughly the same temperatures.

      The main concern is feeding – the frog may be reluctant to feed by day, so you’ll need to provide food at night, so that the anoles do not consume all of it. Provide moths and wild caught insects when possible. The frog will not likely find waxworms and similar foods on the ground, so suspend these in cups among the branches.

      You’ll want to make sure that the frog can shield itself from anole’s UVB light, as too much may cause eye problems. Also it should have an elevated site away from the basking site, so that it can keep itself cool. Barking treefrogs like wide, flat branches, forked limbs, etc., and prefer some plant cover overhead. They are quite stocky and rarely cling onto the glass or thin branches as do slimmer species.

      Spray the frog twice daily (use an instant de-chlorinator in the water) and provide a water bowl for nighttime soaking. Anoles do fine with moisture, as long as they can dry out under lights and the substrate does not remain soggy.

      Hagen Jungle Earth and similar products work well for both species.

      There’s always the concern that a parasite benign in one species may be dangerous to another (a real problem in turtle-snake exhibits) but I have not run across this regarding frogs and lizards.

      Good luck, enjoy and please let me know how it works out.

      Best regards, Frank Indiviglio.

  6. avatar

    Hi, Frank — My question has to do with my five tree frogs I have living in a terrarium on my lanai. I live in FL so the outside temperatures are perfect (they were caught in the wild as very tiny frogs, smaller than 1/2 the size of a dime, and now they’re full size)…as winter temperatures roll in, should I be concerned about putting a blanket over the terrarium? All of our wild tree frogs around seem to adjust fine to the winter weather change but I want to make sure I’m doing the right thing…also, I feed them daily right now, should I reduce that to once/week with the colder temps? Thanks for your help!

    • avatar

      Hello, Frank Indiviglio here.

      Thanks for your interest in our blog.

      Please let me know where you are in Florida, and your average and lowest temperatures, and also the type of treefrogs that you have. They should be fine they are native, and their appetites will slow down in tune with the weather, but I can provide more specific advice if you send along a few more details.

      Best regards, Frank Indiviglio.

  7. avatar

    Hey Frank,
    Thank you so much for your input. Everyone has been living together for about a week now and I’ve been keeping a close eye on everyone. They all seem to be enjoying their new home. I am feeding twice a day, one first thing in the morning and the second an hour after I turn off the lights. The frogs have even started calling which they have not done since I got them. The mixed terrarium has given me some great oppertunity for pictures. Thank you again.

    • avatar

      Hello Jennifer, Frank Indiviglio here.

      Thanks for the update.

      Splitting the feeding as you describe is ideal…I think you have many interesting observations to look forward to.

      Good luck and please keep me posted.

      Best regards, Frank Indiviglio.

About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
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