GREEN TREE FROG CAPTIVE MANAGEMENT
by : Ben Luxton

INTRODUCTION
This article describes how to keep green tree frogs in captivity and discusses how some of the problems associated with amphibian maintenance can be overcome. The discussion is based on experiences of Sciences of the University of South Australia.

ESTABLISHING A HABITAT FOR GREEN TREE FROGS
The most important feature of any amphibian terrarium is the provision of moisture and warmth. Amphibians are pikilothermic, relying on their environment for heat. They absorb a certain amount of oxygen through their moist skins and due to this high level of epidermal permeability may desiccate if sufficient moisture is unavailable. Thus warmth and moisture must be provided in a tank containing materials that are not likely to rot. The following steps describe the stages in setting up such a tank.

Selecting the tank
Select a suitable sized aquarium. One 60cm aquarium is big enough to accommodate 2 medium sized frogs. The glass aquarium lid, which is usually supplied, will unfortunately not be of much use. It seals too well, allowing the moisture within the environment to build yp and condense on the walls obscuring your vision of the animals and also doesn't permit adequate air flow, leading to the build up of stale air which in the long run will be detrimental to your frogs. A close fitting lid combined with ventilation will have to be constructed from wood to fit the tank you have chosen. an area at one end of this lid should be covered with fly mesh to allow adequate ventilation through the tank but not allow all of the humid air or animals to escape.

Cleaning the tank
The tank should be thoroughly cleaned. Warm soapy water must be used on the inside and rinsed thoroughly: glass cleaner may be used for the outside but definitely not on the inside. The frogs high level of epidermal permeability may result in the uptake of noxious chemicals with fatal consequences.

Terrarium medium
A 2cm layer of activated charcoal (obtained from pet stores) or washed garden centre charcoal should be placed in the bottom of the tank to assist.

Plants
The type of plants you intend to put in the terrarium ultimately depend on where the tank is going to be situated. If the terrarium is going to be placed in front of a window and will receive indirect sunlight, obviously the plants will do much better. Direct, scorching sunlight should be avoided as the extremes of temperature may prove to be too great for the amphibians. If a low light situation is to be used then "Growlux" or fluorescent tubes may need to be used to provide sufficient lighting for the plants. A tube can be easily set yp by attachin it to the back of the tank on the outside or placed on the top which will also assist in the focussing of attention on the display. Plants commonly used in terraria are equally suitable for the amphibian environment. Plants such as Syngonium (White Butterfly), Devils Ivy, Pepperomia species and "Moses in the Cradle", (Rhoeo discolor) are hardy and grow extremely well in this type of set up.

Point to remember: the frog will jump all over the plants therefore the plants must be suitably sturdy and not damage the amphibians through the emissions of toxic saps when broken or posses spines or barbs.

Don't clutter up the viewing side of the tank with plants.

Cosmetics & Practicalities
The final step in the establishment of the frog terrarium involves the placement of surface materials within the environment. It is a good idea to put a buffer zone of some kind between the soil ares and the water container as the movement of the frogs from one area to the other wil soil the water very quickly. Small rounded pebbles, rocks or stones can be used around the water dish to provide this buffer zone. Feature materials such as small logs, stones, leaf litter and white gravel can be used effectively in setting off the entire enclosure to you satisfation.

FEEDING TIPS
Frogs require the stimulus of moving food to induce them to feed and therefore live invertebrates are required for the maintenance of these animal (Blackshaw et al. 1987).

Commercial mealworms (readily available from pet stores) can form a staple, standby diet but a variety of invertebrate material is preferred. Moths, flies, cockroaches, grasshoppers and slater are an example of the variety of invertebrate material that will be eagerly consumed by the frogs. Some larger frogs will feed on small, pink mice but this may contravene the Animal Ethics policy at you school. None of these items should be -resented as sole diet as deficiencies will result. Colonies of mealworms, cockroaches and gents are easily maintained within the laboratory (Morris, 1986). The food should be offered in a shallow bowl to prevent the possibility of the food items drowning and rotting within the damp environment.

In general, this animal should be offered food once a week, especially in situations where the animal is sedentary and spends the majority of its time in the corner of the terrarium. Animals receiving a good deal of exercise can be offered more food as required. Captive amphibians, as with the majority of animals, are prone to obesity and therefore the food intake must be monitored to ensure the long term health of the individual.

HANDLING AND GENERAL CARE
On the whole Litoria caerulea are extremely docile creatures if treated carefully, and will sit calmly in the open hand (Figure 2). Should the frog become agitated it should be gently cupped in your hands and replaced in the cage and left alone. Never restrain a frog that you are intending to have as a pet. If the frog is comfortable with you then it will oblige you by sitting quietly. If you force it to comply you may damage it. The fat deposits on a frog are carried at the base overlying the two pelvic bones which come to a sharp "V" at the back of the animal (Figures 3a and 3b). If these bones are sticking out conspicuously, with the sides of the animal falling away sharply then that animal is not feeding appropriately. Offer it a more varied diet, especially flies or cockroaches as these tend to b e a bovourite and check the temperature of the environment. A temperature falling between 25 and 30 degress Celsius should be maintained somewhere within the tank environmet. Loioria caerulea alter their colour depending upon the background colour of their environment from green to brown. This is a normal condition of the species and need not cause undue distress.

Artificial humidifying of the environment may be necessary and can be extremely beneficial to both the frogs and the plants. Use a small spray of water but be careful to remove any live food from the cage before spray misting as it may well drown within the feed dish. To date very little is known about the dieseases that affect frogs and consequently no information is available (Tyler 1992 pers. com.) Despite all precautions, some tree frogs may die. However, I hope that the information above, learned from years of experience with these delightful and beautiful creatures may allow you to provide the best possible habitat for your frogs.

General information about frogs can be found in Tyler (1977,1978).
by : Ben Luxton

REFERENCES

• Blackshae, J.K. & Allan, D.J. (1987),
  Principles of laboritory animal management, (3rd ed.), 90-95
• Morris, B. (1986). Mealworm maintenance.
  Adelaide: SA Museum Information Centre.
• Tyler, M.J. (1977), Frogs of South Australia. (2nd ed)
  Adelaide: South Australian Museum.
• Tyler, M.J. (1992). Amphibians of South Australia.
  Adelaide: Handbooks Committee.
• Tyler, M.J. (1992) Personal communication