Frogs and other amphibians make really fun and interesting pets. Some of the things like set-up of the tank and making insect traps can be a bit tricky, so get an adult to help you with these. But after set-up, they are fairly easy to keep.
Kinds of frogs that you can keep as pets in NZ
Brown tree frogs (Litoria ewingii), Southern Bell frog (Litoria raniformis), Golden Bell frog (Litoria aurea), axolotls (Ambystoma tigrinum), Fire-bellied newts (Cynops pyrrhogatser and Cynops orientalis). It is against the law to keep any of the native frogs.
You must not release axolotls or newts into the wild, as they are not found naturally in New Zealand and could cause big environmental problems if they become wild. Also, it is important not to let any pet frogs or tadpoles back into the wild, because they can spread diseases that they may have picked up in captivity to other wild frogs.
Where you can get pet frogs
Fire-bellied newts and axolotls can only be bought from pet stores, because they don’t live in the wild in New Zealand. Non-native New Zealand frogs can be bought from pet stores or garden centres or collected from the wild as spawn or tadpoles. Tadpoles and spawn are found in still water, so check ponds, wetlands or even farm animal drinking troughs. Be careful where you collect because it is illegal to collect plants or animals from wildlife/national parks or reserves without a permit from DOC. Also, if it is not your land, it is a good idea to ask for permission from the owner.
For Brown Tree frogs, look for small (15-20 eggs) clumps of spawn clinging to vegetation near the water’s edge. Both Bell frogs lay large clumps of spawn in pond weed. Bell frog spawn floats during the first few days after being laid, then becomes submerged just beneath the water surface. It can be really hard to tell different species of tadpoles apart when they are little. A good idea might be to go looking for frogs at night with a torch (make sure you do this with an adult) so that you know which type of frogs your tadpoles came from. Normally, though, if you see big tadpoles (more than 5cms long) they will be Bell frog tadpoles. It is best not collect wild adult frogs for keeping in captivity, as they don’t deal well with being put in tanks.
What you need to keep frogs
All amphibians need a closed tank, because frogs and newts can climb glass and axolotls can jump out of the water. Closed tanks also stop live insect food from escaping. Glass or plastic containers make good tanks but at least one of the sides (frogs only) or the top (frogs, newts and axolotls) needs to be made of mesh to let air in. Very fine mesh like muslin or cheesecloth works well because you can keep really small insects like fruit flies from escaping. Size and shape of the tank depends on the size and species and number of amphibians you want to keep. Minimum tank sizes are given here, but your amphibians are likely to be healthier if given a larger tank.
Brown tree frogs like to climb, so a tall tank is best. For two to three adults, the minimum tank size is 450mm high x 250mm long x 250 mm wide.
Bell frogs aren’t as fussy about the height of the tank because they don’t climb as much. But, they can grow quite large so you will need a fairly large tank. The minimum size for a tank with two small adults is 600mm long x 300mm wide x 300mm high. Larger tanks (900-1200mm long x 450-600mm wide x 450-600mm high) are good for a small group of adults.
Fire bellied newts do well in glass fish tanks, where the minimum size for two newts is 600mm long x 300mm wide x 300mm high. They need a lot of water, so ensure the tank you choose is watertight.
Axolotls are totally aquatic, so do well in a fish tank with a large-sized gravel bottom, like what you would give large goldfish. Minimum tank size for two axolotls is 900mm x 380mm x 380mm. The length and width of the tank are more important than the height, because they like to swim around the bottom of the tank, but a minimum water depth of 25cm is needed.
Amphibians are all sensitive to chemicals in water, so tap water is not the best, but you can use it if you get rid of the chlorine in it. You can do this by leaving it overnight in a clean bucket, or you can use dechlorinators (normally used for fish tanks) found in pet stores. It is better to use rainwater if you live in a non-smoggy area, or filtered water. It is a good idea to check the pH of the water if you have newts or axolotls (you can get pH test kits from pet stores). Between 6.5 and 7.4 is best for newts and 7 and 8.5 for axolotls. pH can be changed with products from your pet store. Amphibians need land areas wet too, so keep a spray bottle of water handy to water the tank. The tank doesn’t need to be soaking wet, just spray it once every couple of days so that it looks like there’s just been light rain in your tank. The amount of water needed depends on the species, and is discussed below.
The Bell and Brown tree frogs live mainly on land, but like to bathe, so give them a container of water with a half-submerged rock or branch (do not use manuka or kanuka as this can poison the water) for the frogs to climb easily in and out. Whistling frogs spend a little time in shallower water, so a small “pond” will do. Bell frogs swim more, so will need a bigger and deeper container of water.
Newts do best in tanks that have more water than land because they like to swim a lot. A water depth of around 20cm is best. You don’t need a water filter, but it could be helpful.
Axolotls live completely in water, so simply fill their tank with water to a depth of at least 25cm. You might want to get a fish-tank water filter because it will mean that the water can keep clean for longer. If you don’t have a filter, half to a third of the water needs to be changed every few days.
For how much land to have, a good guide is: frogs need mostly land area in the tank, newts need about half land, and half water, and axolotls need all or mostly water, so the base would be fish gravel on the bottom of the tank, just like for goldfish.
Large round fish gravel makes a good tank base, but make sure the size of the gravel is too large for the axolotls to eat. A good idea for making land for newts would be to put some large rocks into the tank and half fill with water so the top of the rocks stick out of the water. For frogs, soil, leaf litter or sphagnum moss (have a look in garden centres) can be used too. But, soil and leaf litter can contain diseases and pesticides. If you caught your frogs as tadpoles or spawn, you could collect soil or leaves from the same area, as a healthy group of frogs means the soil should be fairly safe.
Plants, Rocks and Logs
It is important to include plants and logs or rocks for your amphibians to climb and hide under, as it makes life more interesting and being able to hide will make your pets feel safer.
For frogs, plants can be either potted or planted directly in the soil at the bottom of the tank. Plants that like it shady and wet do best in frog tanks. Try ferns, moss, or bog plants. Rocks, logs and dead or live leaves make good hiding and hibernation spots (important if the tank gets cold). Brown tree frogs like to hide in clumps of grass in the wild so may enjoy a small tussock in their tank.
Axolotls and newts have a lot of water in their tanks, so water plants are great (but newts still use land plants, especially moss). There are some cool water plants for fish that are potted in a small plastic basket which you put straight into the water. Axolotls enjoy hollow logs, pieces of plastic drain pipe or hollow fish ornaments to hide and sleep in.
Keep a look out for any fungi growing on logs, leaves or plants, and remove anything that has fungus on it, because it can be harmful to amphibians.
The amphibians you can keep in New Zealand don’t really need any heating. Axolotls and newts shouldn’t need heating if kept at comfortable room temperature. However, frogs kept in a shady place inside may appreciate a fluorescent light or desk lamp directed on the tank during day-time for them to “sunbathe” under. Exposure to light also helps frogs get enough vitamin D3.
(Please make note that axolotls should have either no gravel at all or large pebbles as a substrate – too big to be eaten – as gravel or small stones may become impacted in their guts and this is one of the commonest causes of death in captive axolotls).
How long do pet frogs live
Captive frogs can live up to 15 years on average. The oldest captive frog recorded is the European Common Toad (Bufo bufo), which lived for 40 years at the London Zoo. Most captive fire-bellied newts live between 10 and 15 years, but could get up to 28 with really good care. Captive axolotls can live for 10 to 16 years. A few captive axolotls have lived for 25 years. So bear in mind if you have a pet amphibian you may be passing it on to your children or your parents to look after when you leave home!
Will amphibians eat each other?
Yes, amphibians will eat other smaller amphibians. This is why it is not a good idea to keep amphibians of different sizes or species together. The only exception to this is the two species of Bell frog, which can be kept together if the frogs are all the same size. But, be very careful with sizes, because Bell frogs will eat others that are a tiny bit smaller.
What do I feed them?
Amphibians need live food. They will eat any animal as long as it moves and can fit in their mouth. However, some foods suit amphibians better than others. A good rule of thumb for food size is to choose food that is smaller than your pet amphibian’s head. Try to feed your amphibian lots of different foods, as this will help them stay healthy.
There are plenty of insects that make good sources of food. These can be caught from your own garden (or house!). There are some ingenious home-made inventions around for catching flies and moths. You can also have great fun catching insects with butterfly nets for your amphibians. Good ideas for netting insects include scraping the net through long grass, or leaving the outside lights on at night to attract moths, which you can then net. You could also scrape up some leaf litter or compost and put it into your frog’s tank, as these tend to contain lots of edible insects. However, remember there is a risk of adding diseases to your tank when you add leaves or compost. Additionally, you could breed your own insects or buy them from pet stores.
Very small frogs and newts (less than 1.5cm) can be fed fruit flies or white worms. Small to medium size (1.5 – 7cm) frogs can be fed flies, waxmoth larvae, slaters and small cockroaches, crickets, locusts, and moths. Good food sources for large frogs (more than 7cm) include large crickets, locusts, moths and cockroaches.
Axolotls are a little different because they can be fed small chunks of meat as well as live insects (dangle them into the water in front of the axolotl’s mouth). They like food that either moves or smells a lot. Earthworms and oxheart strips are favourites.
Feeding your pet amphibian too much (especially too many waxmoth larvae) will make them fat and unhealthy. Feeding once or twice a week should be enough. It is best not to feed your frogs biting animals like spiders or bees, as they might bite your frog. Also, monarch caterpillars and butterflies and magpie moths and caterpillars are poisonous.
Insect traps – as many frogs need live insects there is always the problem of keeping up with supply and demand. There are a range of excellent and cheap fly traps.
How do I keep tadpoles?
Tadpoles can be kept in an ordinary fish bowl, with some oxygen weed and stones for them to hide under. The NZ Litoria tadpoles don’t seem to be as fussy as some species of tadpole about having lots of oxygen in the water, but an air pump or oxygen weed can be used to boost oxygen levels. The water needs to be changed regularly before it gets yellow.
NZ non-native tadpoles naturally eat plants. They can be fed lettuce, fish food rabbit chow or fish algae wafers. If feeding them lettuce, either use organic lettuce or wash the leaves before putting in the tank to get rid of pesticides. You can freeze your tadpole’s lettuce if you want to keep it for a long time. Remember if using flakes, the tadpole’s water needs to be changed more regularly as the food disintegrates. Try to give your tadpole a varied diet. Water needs to be changed before it starts to become yellow. It is best to use aged filtered water, as compounds in tap water can be harmful to tadpoles. To make this, simply leave a container of filtered water overnight.