*Frog

Litoria caerulea – Green tree frog

Introduction

The Green tree frog is one of Australia’s largest frogs, reaching up to 11cm in length. The species is by its large body size and vibrant green skin colour. Green tree frogs are one of the most widely found species of amphibian in Australia, found in every state except Tasmania and Victoria. They occupy a variety of habitats from urban areas through to forests, woodlands, wetlands and heathlands. In some areas they often take up residence in suburban houses, around water tanks and shower blocks.

Green tree frogs diet consists of insects, hence they are often found on window sills or near outdoor lights, eating the insects that are attracted to the lights. The Green tree frog is kept in zoos and as a pet and has a lifespan of up to 16 years when kept in captivity.

Environment

Temperature

The ideal environmental temperature range for the Green tree frog is between 20 and 25°C. but the water temperature does not have to be within this particular range. Heat can be provided by using heat pads, or ceramic heat lamps. If a ceramic heat lamp or other type of heat emitter is provided it should be fitted to the outside of the enclosure to prevent the frogs coming into direct contact with it or a hot surface which can lead to burns to the animal. Thermostats must be used to control heat sources and prevent overheating of the enclosure. Temperature in the enclosure should be stabilised prior to moving frogs in. A good temperature gradient within the enclosure is essential for frogs to be able to choose their desired temperature. The temperature gradient is created by placing the heat source at one end the enclosure so that frogs can move away from the heat source to cooler areas of the enclosure if they so choose.

Ventilation

Green tree frogs require good ventilation. It is recommended to have secure mesh lids on aquariums and tanks for them to have adequate ventilation, while preventing them from escaping. It is recommended to have a lid constructed of a metal framework with mesh attached. Frogs are extremely capable of escaping enclosures due to their ability to climb and jump and squeeze their bodies though small gaps. For this reason, care must be taken to ensure enclosures are very secure.

Humidity

Green tree frogs require a humid environment. A slight misting or spraying of the frog and enclosure should be carried out daily to keep the humidity and moisture levels adequate. It is essential to use filtered water rather than tap water when misting or spraying to prevent frogs coming in contact with chlorine and other substances found in tap water which can be potentially harmful to them.

Lighting

Green tree frogs require a UV light tube as well as a ceramic heat lamp (if more heat is required) in their enclosure. The UV light should be a specific light that is designed for reptiles and amphibians and emits UV-B, this can be purchased from a pet store. The lighting should be switched off at night and on during the day to replicate the natural light cycle. It is recommended to use electrical timers to ensure lighting is controlled appropriately to provide a natural day/night cycle. Daylight hours should be 10 – 12 hours.

Enclosure

Although custom enclosures can be made to house Green tree frogs, it is probably easier to purchase a commercially available “terrarium” similar to the one pictured below from a specialized pet/aquarium shop.

Glass enclosure with branches and leaves

Spatial requirements

Green tree frogs should be housed in glass aquariums/tanks and can be kept individually or with multiple animals in an enclosure. It is recommended to use an enclosure with a minimum size of a 60cm cube for a green tree frog. Housing multiple frogs together will require a larger enclosure with 3 to 4 frogs housed in an enclosure that is 60cm long x 100cm high x 60cm wide making a more appealing display than a single frog in a smaller enclosure.

Floor

Enclosures used to keep frogs should be made from glass or some other material that is not prone to water damage and have an area that allows the animal to completely submerge in water and an area out of the water for frogs to sit, hide, feed and climb. The area out of the water can have a substrate such as coco fiber or aquarium gravel (although it should be made certain that this is not ingested at feeding times). Large rocks such as “river stones” can be used in the water areas for aesthetics although this is not needed and can make the water body harder to clean.

Furniture

Frog enclosures should be furnished to provide frogs with an area similar to that of the environment they would live in the wild. As this species is arboreal, the furnishing should provide the frogs with climbing opportunities and elevated perching. The furniture can include logs, real and artificial broad-leafed plants, ornamental rocks, branches, vines and other hiding places. It is important to provide hiding places so that frogs can retreat to privacy. All furnishings must be smooth, clean and stable to prevent injuries that may be caused by unsecured furniture falling onto the frogs. Although it does not look natural other plastic furnishings can be used such as plastic plant pots and PVC pipes. One of the main advantages of these ‘unnatural’ furnishings is the ease in which they can be cleaned.

Nutrition and Water

Water

Water is essential to all amphibians and must be provided at all times. However untreated tap water should never be used as it can prove harmful to amphibians due to the chemicals it often contains including chlorine, fluoride and copper.

The two common ways to provide safe clean water that is free of harmful chemicals for a captive Green tree frog are discussed below. However, regardless of which of the two systems that is used, it should be ensured that the frog is provided with access to a water body containing clean, conditioned/filtered water at all times. Instead it is advised that if you are keeping frogs that you invest in a relatively inexpensive counter top water filter that can be purchased from a hardware store to remove any potentially harmful chemical compounds from the water.

When purchasing a “counter top” water filter it is essential that it does not filter the water through reverse osmosis as this water can be too pure and can cause the death of the amphibian.

Water can be provided in a bowl or container such as a plastic food container, plastic plant saucer or similar that is large enough for the frog to submerge in and contains still water. This method does not require an aquarium filter and can therefore be easier to set up and makes changing the water easy as you can just remove it from the enclosure and tip it out. However, if water is provided in this way, it should be emptied and changed daily conditioned/filtered water. Otherwise pollutants such as urine and faeces can cause the water quality to decrease. As the frogs are likely to swim, hydrate, urinate and defecate in the water, it’s essential that it is changed daily. Even if the water does look clean, it should still be changed as it could contain an amount of invisible pollutants such urine.

A water body that is cycled through an aquarium filter This water should be treated the same as keeping a fish in an aquarium with regular testing of water quality such as pH, ammonia, nitrate and nitrite levels (a good quality water testing kit from a Aquarium store should be used for this). Water changes need to be also performed regularly with a general rule of a 10% water change completed on a weekly basis. The easiest way to do this is to use a siphon to empty the desired amount of water out of the enclosure and then topping it up with water that has passed through a counter-top water filter. There are numerous types of aquarium filters suitable for this purpose available in aquarium shops including canister filters. When purchasing a filter, it should be ensured it is of an appropriate size to the amount of water it is filtering. A good guide to this would be the filter cycling the water through the filter 4 to 6 times per hour. This system is harder to set up but may be more aesthetically pleasing for the humans viewing the frog but doesn’t really have a greater benefit to the frog over the first method discussed.

Nutrition

Green tree frogs’ diet consists of a variety of invertebrates. In the wild, Green tree frogs are commonly found near outdoor lights where they catch insects that are attracted to the light.

The most commercially available insects that are suitable for feeding Green tree frogs include crickets and wood roaches. These can be purchased from most reptile and pet stores.

A recommended diet for Green tree frogs is:

    • Young frogs: 2-3 crickets/wood roaches fed daily
    • Adult frogs: 2-3 crickets/wood roaches fed 2-3 times per week.

The insects offered should be of appropriate size for the frog. For example, a large adult cricket or wood roach would be too large for a young Green tree frog to eat but an adult frog would not have any issues eating something of this size.

Insects should be dusted with a calcium and multivitamin supplement powder to ensure that frogs’ calcium and vitamin needs are being met. An appropriate calcium and multivitamin supplement powder can be purchased from most pet and reptile shops. When feeding, the insects should be offered from forceps to ensure that the frogs are eating all of the insects that are offered. If they are just scattered in the enclosure, some of the insects may hide before the frog gets a chance to eat them. This is also important if housing multiple frogs in one enclosure to avoid one or two individual frogs eating all the insects and leaving the others to miss out.

Some literature may indicate that you can feed vertebrate animals such as mice to Green tree frogs but this is not recommended and should be discouraged as high protein foods such as these can lead to health issues such as obesity and high cholesterol levels.

Hygiene

Water quality is important and should be kept of a high quality as discussed in the chapter on water. It should also be noted that frogs and amphibians can absorb chemicals through their skin so it is important that chemical sprays and aerosols are not used in the vicinity of the frogs. If the frog enclosure is to be disinfected, the frogs should be transferred to a separate temporary enclosure such as a plastic container while this is taking place to ensure the animal does not come into contact with the disinfectant. Other “hygiene routines” to follow include:

    • wearing disposable gloves when handling the frogs
    • regular removal of feaces from enclosures and water bodies
    • disinfecting the enclosure with a bleach solution and rinsing thoroughly to ensure there is no residue of the bleach left in the enclosure.

More

Handling

Frogs in general do not respond well to being handled and this act can cause stress. It is therefore recommended to only handle frogs when necessary. For example, removing a frog from its enclosure to a holding tank for cleaning or enclosure maintenance purposes. Due to the sensitive skin of amphibians, they should always be handled with either latex or vinyl disposable gloves. The use of disposable gloves will help prevent the frog coming into contact with bare hands that may have been exposed to chemicals or diseases that could prove harmful to the animals.