Raising Tadpoles in Containers and Ponds
Caring for a few tadpoles and watching them turn into frogs (metamorphose) is a fascinating and rewarding activity for young and old alike. It is also becoming more useful for scientific reasons, too. There are still many things we don't know about frogs while many species worldwide are disappearing before our eyes. Some of the information about a frog's life cycle are far easier to obtain from frogs and tadpoles in captivity.
It is also much easier to discover if any diseases are active as sick or dead tadpoles are hardly ever found in the wild. With the severity of droughts (becoming more common all the time), the rescue of tadpoles from dwindling puddles or overcrowded frog ponds is that much more important. Do remember, though, that if you are in an area where mosquito-borne diseases like Dengue and Ross River Fever occur, you MUST ensure that your tadpole enclosures do not breed any mosquitos. If you live in Queensland, please refer to the bottom of this page for specific legal information important to your tadpole keeping.
Tadpoles are generally easy to keep IF you have them set up CORRECTLY. If you are considering doing a tadpole rescue, please remember the following:
- tadpoles need a certain amount of time (usually measured in months) so don't collect them unless you can commit for the time they need
- depending on what you have available to feed them, you might need to spend some money for food and you will need sufficient rainwater for the entire time of their development - be sure you have all your supplies ready before the tadpoles arrive
- space to develop - a rough rule-of-thumb is no more than 2 tadpoles per litre of water - so only collect what you have containers to accommodate
- sufficient oxygen which can be in form of an acquarium aerator or the right plants with a little sunshine
- a watchful eye during metamorphosis; if the tads have come from somewhere else, they will need to go back so make sure they don't escape; if you have rescued a ground dwelling frog, they will need help to get out at the right time as they can't climb out like the tree frogs do
Where Are Tadpoles Found?
There are many places to find tadpoles such as a nearby stream, a swamp, a drainage canal, a dam, pond, lake or billabong. (Remember to think about your own safety in approaching bodies of water - there might be a risk from weeds which your legs can get tangled in, steep slopes, slippery bottoms, etc. In the tropics, there might also be risks from Leptospirosis in the water, dengue mozzies, etc. - children should bring an adult to help collect the tadpoles.) Sometimes frogs lay eggs in places we would rather they didn't like a swimming pool, a flooded curbside or an ornamental container in our garden that filled with water during a heavy rain. If you want to collect tadpoles to raise in tanks or you have a new frog pond that you would like to stock, we strongly recommend that you read our page "Before You Collect Tadpoles". There are serious disease problems around most of Australia and you would not want to find yourself with a tank or pond with contagious animals in it (disinfecting a contaminated pond can be a labourious, dreaded task). Some states also have laws to restrict this activity so you need to check first.
After you have read the tadpole distribution information, then you are ready to rescue some tadpoles from a rapidly dwindling puddle or receive extras from a frog pond owner in your neighbourhood. One of the most common questions about collecting tadpoles is how to avoid collecting the tadpoles of cane toads (referred to as TOADpoles for clarity). To tell the difference, visit the Toadpoles vs Tadpoles page.
Some people believe that collecting any animal from the wild is wrong and some states have regulations to control this. In Queensland, it IS legal to collect and keep tadpoles until they have turned into frogs and you do not need a licence or permit to KEEP tadpoles but you will need a permit to MOVE/rescue tadpoles (see the Keeping section - QLD regulations page for more details). If you have a Recreational Licence to KEEP frogs in captivity, you cannot have any tadpoles at all. If the tads were collected on your own property and kept in containers on your own property, then this is not "moving" them.
Under the current regulations, once tadpoles have metamorphed (this means when they leave the water - not when they grow legs!), they must be released back to where they were collected from or close to it within seven days of metamorphosis. This regulation, unfortunately, is completely inadequate when it comes to knowing if the tadpoles picked up any diseases when they were in the wild. If you wanted to be sure they did not have chytrid fungus, for example, you would need to keep the juveniles for at least one month before release.
Most of the known frog diseases (including chytrid) affect the little metamorphs very strongly and cause them to die within the first three weeks after they leave the water. If you release all the metamorphs in seven days (as regulated in QLD), you won't know if they were exposed to disease or not. If you live in QLD, it is up to you whether you abide by the Queensland regulation. IF you are able to find enough tiny food to keep your metamorphs well fed for four weeks, then you will be able to release frogs which you can be more confident don't have chytrid fungus. Other diseases such as viruses could still be present and there is no possible holding period that is long enough for them. Feeding metamorphs can be a difficult task, especially in drought affected areas because of the dwindling food supply - so if you CAN'T find enough food, then it would be better to release the metamorphs quickly and leave it to their instincts and talents to find their own food.
There are genuine conservation benefits to collecting tadpoles from the wild which include:
- Tadpoles normally don't survive in the wild as well as they do in captivity (with the right care) because they are food for other animals and sensitive to changing conditions and weather patterns. By raising tadpoles in captivity, more of them can reach metamorphosis to begin their lives as frogs.
- The learning experience children and adults get from caring for tadpoles and watching them change into frogs helps keep nature and the environment 'in the picture'. The more urbanised our towns and cities become, the less connection with nature we have. After awhile, it becomes 'out of sight - out of mind' and we lose sight of its importance and the needs of the species that need a healthy environment to live. Raising tadpoles and thinking about their needs reminds us that nature is still there and needs to be looked after.
- Many professional scientists, veterinarians, biology teachers and wildlife managers started out as a keeper of native animals when they were young. By being allowed to care for and learn more about native animals, their interest was nurtured and kept growing until it became their chosen work. Such career choices are far less likely if the occupant has not had a long term interest and interaction with nature and wildlife.
Eggs before tadpoles
If you have actually found eggs to collect, then there are some minor guidelines for them. Set up the container you plan to put the tadpoles in (according to information below) but put the eggs in instead. They will appear to be elongated between 24 and 48 hours after being laid and will leave their gelatinous eggshells about another day after that. They are very tiny for several days but start to grow quickly. Because they are so small, it might be tempting to just keep them in a small bowl of water and transfer later. We don't actually know why but, for some reason, the eggs die if they are in too small a body of water. There is also the factor of trying to move tiny little bodies only 3mm long to another container without hurting them. So if you are starting with eggs, put them straight into a large container which is ready to hold the tadpoles.
The very first step in setting up your tadpoles is asking what are you going to put them in. The best containers are shorter and wider as opposed to taller and narrower. This has to do with the oxygen availability. Any container made of metal is out of the question, including those coated with enamel or porcelain. Glass is good but consider the weight of it when the container has to be moved or cleaned. Broccoli boxes (foam boxes; styrofoam for our American friends!) are also a good choice. They are lightweight, insulated and are wide. The plastic molded kiddie pools are also good if you want to have a large number of tadpoles and you have the necessary water available.
Plastic is good but don't use a bucket that has already been used to hold any cleaning products or other chemicals. The 36cm plastic 'small critter tanks' sold in pet shops are also a very good choice but only for a small amount of tadpoles.:
- they have snap-on ventilated lids to keep the tadpoles in and other things out;
- you can sit and watch the tadpoles easily;
- you can move the tank to where it will get limited sunlight sometime during the day; and
- the snap-on lid will be useful when the tadpoles metamorph (important if you have rescued tadpoles from outside your neighbourhood - the metamorphs will have to be returned to where you found them)
- another of the same type of tank can be setup for the little frogs until you are ready to release them
Sand on the bottom of your chosen container can be very useful for tadpoles but we have noticed in tropical Australia that mozzies seem to be more attracted to tanks with sand on the bottom. Tadpoles do seem to like to forage around in the sand looking for microbials but sand will make it harder to clean which is a big factor if you are handling a large number of tadpoles in the tank. Where you get the sand is important. Beach sand is great but you must make sure that every trace of salt is removed from it before it can be used. (There may be local restrictions about collecting beach sand so you might want to check that out first.) To leach beach sand, you need to wash it throughly until the water comes out clear. Then divide up the sand into several containers such as plastic ice cream containers. Fill with sand halfway and then fill with water to the top, stir, then leave sitting for a day. Drain and rinse and refill. Repeat this procedure until you have done about 6 or 7 water changes. By then, all the salt should have reverse-osmosed out of the sand.
To save the hassle of leaching salt, use river sand instead from a section of river that is not tidal. Quarry sand can also be used but the it should be soaked the same way as the beach sand for one or two water changes. Aquarium gravel is only recommended if it is the tiny, very round pebbles. Avoid the glass or other sharp edged gravels or larger pebbles.
Arrange the sand along the bottom til it is about half an inch/15mm deep. Then carefully add the rain water (see Water below). Let the tank sit for a few minutes so that the sand settles and the water clears. Then you can add plants (see Oxygen below) and tadpoles. (If you are caring for a batch of tadpoles which has turned out to be diseased, don't bother with the sand as it will make the frequent water changes more difficult.) If you are in the tropics, the sand will actually attract more mozzies to lay eggs in that water so avoid the sand for tropical rescues.
How many containers will you need? It depends on how many tadpoles you plan to accommodate. The 'best practice' is that you should have a litre of water for each tadpole by the time it gets to adult size but for smaller species, you can put two tads per litre. When they are small, you can fit more than that but you will need to divide them up as they get bigger. A container that holds 20 litres of water (about 4 gallons) should only have 20 or 30 full grown tadpoles in it. Be aware that overcrowding tadpoles causes a whole array of problems and increases the amount of work you will need to do dramatically.
Many people ask about snails in the tadpole tank. If you are in the USA, snails should be removed and a full water change done immediately after because snails can carry larval trematode worms (flatworm parasites) which attack the tadpoles and cause deformities. (The deformed frogs problem infamous in the US midwest is caused by these larval parasites.)
Tadpoles have gills so they need really clean water just like your aquarium fish. If you plan to get some tadpoles, you'll need to get your water ready before you bring the tadpoles home. The best practice is to use rain water but there will be some who can't use rain water.
Are you in an area of industrial contamination of your water supply? Are you in an area that suffers from acid rain? Are you in an area of drought? Then you will need other sources of water.
|distilled, Nobles Pure, or reverse osmosis||you can purchase distilled water or purify your own with a reverse osmosic filter||ready to use for your tads|
|spring water||can be purchased but the source can be questionable; check with your local consumer agency to see if they have any information about the supplier and their source for the water||ready to use for your tads|
|tap water WITH fluoride||can only be used if you have a reverse osmosis or other special water filter attached which specifically says it removes fluoride||do not use unless the fluoride is removed|
|tap water withOUT fluoride||must be prepared before using for tads||this can be left in open containers out in the sun for four days to allow the chllorine to leach out or you can use an instant aquarium ager, stir and wait an hour|
|ionized water||do not use for tads||do not use for tads|
Fluoride - helpful or yet another cause of frog decline?
Residents in other areas have had to tolerate fluoride in their water for many years but most of Queensland is finding fluoridated water to be a new experience and, so far, it is very problematic. We have received reports of tadpoles dying overnight when setup in conditioned tap water (this process does NOT remove the fluoride) but the greater impact on frog decline is the effects fluoride has on small fish.
Prior to fluoride, small fish like guppies, white clouds and Pacific Blue-eyes were used to control mozzies in ponds while not posing any threats to frog eggs and tadpoles. The use of these species allowed pond owners to comply with the QLD Health Act but also provide a place for local frogs to breed. Fluoridated water has changed all that. The fluoride is causing several dramatic changes in these fish, affecting their behaviour, ability to reproduce and even ability to stay alive. There are studies overseas which reflect some of the same consequences we have observed here and those are:
- a) anorexia - the fish stop eating and slowly starve to death
- b) reproductive failure - they stop breeding
- c) failure to thrive - probably connected to the anorexia (about 97% of all the fish we have acquired in the past two years have died quickly even though we keep them in rain water (they would have been bred in fluoridated water and their health impacts did not reverse when switched to rainwater)
- d) changes in the brain - these fish which were once safe for frog ponds but they are now voracious predators of frog eggs and tadpoles which means no frog can successfully breed in ponds stocked with such fish
We recommend that every Queenslander makes your concerns known to your state government representative. If you have a frog pond, you should ask many questions of your fish supplier as to whether they have a reverse osmosis water filter in use to remove the fluoride from their breeding and sales tanks. If your fish retailer gets their supply from someone else, you'll need to ask them to chase up the question with their source to be sure reverse osmosis water is being used throughout their distribution system.
If your area has already been fluoridated, please do NOT use the hose to top up your ponds. Put aside some very clean buckets to collect your own rainwater for use in your ponds (and for all other pets and bird baths). If your pond has already had fluoridated water used in it, please drain it (down the loo) and get it ready for this year's wet season with new fish and plants. If you have a pond with the breeding fish species mentioned above and have not yet been forced into the fluoridation route, please advertise your excess stock so others who are setting up "unadulterated" ponds can have a "clean" supply of safe and healthy fish.
Back to other suggestions regarding water .....
Many houses have old copper pipes and no amount of aging will remove the copper from the water. If this is the situation in your home, it is far better to collect rain water for your tadpoles. It's easier and cleaner and it falls free out of the sky (if your local council charges for water, then this last point will ring home to you)! When collecting rain water, it would be better to avoid water coming off the roof if your roof is metal. Arrange a series of plastic containers on the lawn instead to collect the rain and then bottle it. Unless you live in an area of acid rain or local industry, rainwater is the best possible water for tadpoles.
Regular additions of fresh water is crucial for the tadpoles. If you have regular rainfalls, you can let the tank sit under a tree or shrub in the garden and allow the rainfalls to refresh your tank. You just need to watch the level to make sure it doesn't overflow and wash away some of your tadpoles. You can scoop out some water when it is too close to the top. If there is more than a five day gap in the rainfall, then you can add some of your already stored water.
If the water is not refreshed often enough, it will start to go off and the tadpoles won't look as good. Watch for cloudiness or any sort of buildup of sediment in the tank. The water doesn't have to be "crystal clear" but you should be able to see the bottom. If you can't, then you can change over about half of the water at least once a week. It is a very good idea to buy an ammonia test kit from the pet shop so that you can monitor ammonia levels. A pH test kit is also a good idea but if you are serious about doing regular rescues or breeding activities, it is worth getting a battery operated pH metre (about $60 in Aust.) so that you can instantly get the right pH levels. Some of the foods we recommend can also turn the water green so they might be used sparingly.
When tadpoles are not doing so well - whether because of poor setup conditions, a contaminant getting into the water, or the tadpoles are diseased - they will change the appearance of the water. A common event is for the water to turn a cloudy yellowish-white and there might be a slimy series of bubbles all along the top of the water's edge and around the edges of plants which touch the surface. This is not a good sign. You might need to sacrifice these by sending them to a veterinary diagnostic lab or a frog researcher so that they can do pathology to see if there is an explanation. You should also handle such tanks with disposable gloves and not use anything that has been used on that tank (such as nets, cups, etc.) for any other tanks you might have.
If you have been refreshing the water at least once a week, then conditions should look good. If it has gone longer than that or if you have a large number of tadpoles in the tank (say 10 tads per litre of water), you might need to do a 50% or even a 90% water change. Carefully scoop out the water and refill slowly so that the tadpoles and any material on the bottom does not get churned up. You can also use a slightly wider version of aquarium tubing to siphon off the sediment from the bottom of the tank before your water change. This will help reduce the percentage of water that needs to be refreshed. (Be careful not to siphon up the tadpoles!)
If the tank has been left too long and the water is so bad that tadpoles are looking poorly, then a complete water change is needed. The easiest way is to set up from scratch another container with fresh rain water in it and gently scoop up the tadpoles using a soft net to shift them into the new tank. Be careful not to bump or scratch the tadpoles. They have soft skin and damage during handling can result in deformities when the tadpoles turn into frogs. Dump the old water down the toilet and scrub the old tank. Rinse very well; rinse the sand thoroughly if you have used it; then put aside for a future water change.
Oxygen and Hiding
According to the calls we get, lack of oxygen seems to be one of the most common mistakes in raising tadpoles. If you are raising tadpoles collected from a stream, it is best to have an aerator running gently; if they are from stagnant water, aeration might be disruptive and stressful so underwater aquatic plants will be essential for providing oxygen. These plants also provide some shelter and hiding areas for the tadpoles and the tads might also eat algae from the surface of the leaves..
Many people choose decorative plants such as water lilies, reeds or floating ferns but these do not provide enough oxygen for the tadpoles and, the amount of the water's surface they interfere with may actually reduce the amount of oxygen available. Leafy plants suspended in the water column are the best type of plants to use. A small amount of floating fern can be used but this should not be allowed to cover over more than 25% of the surface. Even pest weeds such as combomba are okay so long as they are removed from the wild and NOT dumped back to the wild when you're finished with the tadpoles. If the leaves have some algae growing on them, the tadpoles will eat the algae.
In Queensland, Elodea is commonly available in the shops and grows well so you can start with a bunch and spread it around. The tadpole droppings will fertilise it so you'll have more of it by the time the season ends. In the southern states, however, Elodea is a declared pest and not allowed. Whatever plant you use, you want something that is entirely under the water, has a long, stringy growing habit, and lots of small leaves along the length of the stem. Don't put too much plant in your container or it will actually remove some of the oxygen at night. Ten litres of water (about 2-1/2 gallons) only needs two lengths of plant. Another option to ensure good oxygen supply at night is to use an aquarium aerator (with air stone) at night and turn it off during the day.
In order for the plants to survive and produce oxygen for the tadpoles, they will need some sun each day. The tadpoles also need sunlight to obtain vitamin D which in turn helps them process calcium. Position the tadpole containers where they can get an hour or two a day of sun but no more than that. Too much sun will heat the water too much!.
Tadpoles have a long, coiled intestine which is designed for eating plant matter but they love protein when they can get it (in the same way that we love chocolate cake!). If you can find a clean creek, you can collect some leaves from the bottom which have algae growing on them and throw them in the tadpole tanks (not too many!). These leaves will settle to the bottom and the tadpoles can hide in them as well. You can also use paw paw (papaya) leaves which have been frozen first. If you are going to purchase food, any green variety of lettuce (not iceberg or Cos) or baby spinach will be suitable. Rinse well first and then freeze. Organically grown is better so you can be sure it hasn't been sprayed with harmful chemicals before you buy it. Do not use celery leaves or silverbeet (adult spinach)!
There's a saying: "if in doubt, leave it out". If you are not sure if something could be toxic (say a plant in your yard), don't risk it on the tadpoles. You can use other green items for the tadpoles such as sliced up zucchini, green grapes sliced in half, peas (crush slightly to break the outer skin), broccoli (frozen first), green capsicum (pepper). Just feed small amount of these until they are gone before adding any more. We also supplement with spiralina algae discs which can be bought at the pet shop but these do turn the water green so spiralina flakes can be used instead.. A combination of food types is good. Once a week, you can add other types of frozen fish food such as bloodworms and daphnea - it is an excellent protein for the tadpoles and the fish love it too.
Tadpoles need calcium and there are two ways you can add this. Next time you are at the beach, collect some of those cuttlebones. Rinse very thoroughly to remove salt. Break up if they are large - for a container about 30cm (one foot) long, you can drop in a piece of cuttlebone about 4 or 5cm (2 inches) in length. Leave in for the entire time of tadpole development. This method might also deliver some other trace elements for the tadoles.
The second way is to buy liquid calcium. Whenever you have done a water change or there has been at least 10% new rainfall into the tank, you can add 2 drops of liquid calcium supplement per litre of water in the tank into the water. One drop per litre of liquid B complex also helps but check the ingredients on the label carefully. A lot of products marketed as 'health foods' contain nasty additives. (We use the brand Grants of Australia, www.lateralfood.com).
Do NOT feed your tadpoles fish flakes, cichlid granules, bread, any kind of meat product, turtle food, axylotyl food, or pellets made for other animals such as chicken pellets. Tadpoles have a vegetarian intestinal tract; insect proteins (such as bloodworms) are a better protein to use occasionally..
Feeding tadpoles requires small amounts of food frequently. You should only throw in a small amount of food which will be gone in about 8 hours. It is better to throw in food a couple times a day rather than once a day or every other day. Don't put a couple days worth of food in to save time - this will instantly foul the water and you'll have to spend a lot more time doing a partial or full water change. A tadpole's whole life is to eat constantly so keep an eye on the tank and add more food as soon as the last lot is gone.
The Critical Time: Metamorphosis
When you see front legs (arms) on your tadpoles, they are fast approaching the delicate stage of turning into a frog. This is an amazing stage in a frog's life where the sort of special effects that you see in some movies actually take place in real life. At this time:
- the mouthparts completely change
- gills stop functioning and lungs start to work
- the intestinal track changes from the long intestine of a plant eater to the short intestine of a protein eater (insects are almost entirely protein and fibre)
- the skin changes from the smooth, slimy skin of an underwater dweller to porous skin which allows air and water through
- limbs containing a skeleton grow out of a body which had no limbs or bones
- the tail muscle and fin deteriorates and is reabsorbed by the body
When your new frogs leave the water, they might still have a full tail but they can jump. The tail will shrink and be gone in one or two days. (Each species is different so some will leave the water with full tails and others will leave the water with the tail almost gone.) Although most of the tadpoles I've kept simply shimmy or climb up the side of the tank when they leave the water, not all tadpoles will do this. You should put something in the container which the metamorphs can climb onto. It should start under the water and stick out of the top and it should be fixed so it doesn't move. This could be a fat stick or a rock - whatever you can find, so long as it is not made of metal. Water hyacinth is excellent for this but it is a pest (in Australia) so don't dump it back into the wild when you're finished with it! Floating ferns are also good.
Some species are unable to climb out of the water at all, even with a rock. The Ornate Burrowing frog (for example) lays its eggs in flooded grassy areas and has a fast developing tadpole. Ideally, the tadpoles are ready to leave the water by the time the puddle they're in dries up. They simply wait for the water to drain away. This doesn't happen in a tank or pond so the metamorph floats on the surface for a day and then drowns. If you are keeping a ground species, you need to fetch the metamorphs out of the water as soon as their tail is about half its original length. The tail will start to crinkle up and this is a sign that it's time to go!
Another way to allow ground dwelling frog metamorphs to leave the water safely is to setup a separate "tilt" tank which is a typical tank propped up at one end by a brick. Pour the water so that it only reaches about 3/4 of the way up along the tilted floor. Add some underwater plant for oxygen and just shift any tadpoles into this tank as soon as their front limbs have popped out. They will not be eating much after this point so only a very tiny amount of food needs to be put in the tilt tank (just in case). Once in the tilt tank, the metamorph will simply 'walk' out of the water when it is ready and sit in the dry section. Drape a towel over the "dry" end of the tank so that the metamorphs have shelter until you move them to a proper habitat tank setup.
Experience is the best teacher when it comes to metamorphs and the species in your area. But the most important thing when a metamorph emerges from the water is that is should be removed from the tadpole tank immediately. (If you are raising tadpoles which came from your yard or neighbourhood originally, then they can be allowed to simply take off on their own. If you are rescuing tadpoles from another location, you need to catch each metamorph and place it in a tank setup for metamorphs so it can be returned to its place of origin.) Once the new frog has started using its lungs to breathe, it is often unable to use the gills anymore (this depends on the species). If the new frog falls back into the water, it could drown.
If you plan to keep your new frogs for a short time or if you have rescued tadpoles which will need to be returned, you should have a small plastic pet tank ready to place the little frogs in. Put some leaf litter and a small piece of curved bark inside for the frogs to hide in. Some small branches from a bush will also provide hiding and perching space for tree frogs. If you have rescued a ground dwelling species, use some of the same sand you prepared for the tadpole tanks in the bottom of the frog tank but make it a bit deeper. Put some leaves from your trees on the sand to provide hiding space.
Spray the inside of the frog tank with rainwater or non-fluoridated, aged tap water once daily (not too heavily) so that the humidity stays high. A shallow jar cap filled with rain water can be placed on the bottom of the tank - but make sure that the water is no deeper than the the frogs' shoulders when it is sitting so that the frog won't drown (some species do learn to switch back and forth between lungs and gills but some species don't and drown - you'll need to check this for your species so you know which have this problem and which don't).
The new frogs will not start to eat until the tail has been completely reabsorbed. Once the tail is gone, trap some tiny flies (such as vinegar or fruit flies) and put them in the tank. To keep them in the tank, a sheet of thin fabric (like chiffon or muslin) can be stretched over the top of the tank but under the lid. Housefly larvae (maggots) are also enjoyed by metamorphs. Some species of ground dwelling frogs like those tiny dark ants so try some in the tank. If the frogs eat them, you will have another food to use besides vinegar flies. If the frogs ignore them or spit them out, don't use the ants anymore. Do not try to feed green ants or other large ant species to your new frogs -- the ants will kill them. If the tank is on a patio or near an open window, you can also put small pieces of banana or orange in the bottom corners (without the fabric under the lid). The tiny flies will smell the fruit and enter the tank through the lid holes. If you live in green ant country, you will also need to keep your habitat tank inside or else the ants will swarm the tank and kill everything in it.
Ready to Rejoin the Bush
When it is time to release your frogs, the best place to do this is usually at the place you collected the tadpoles from -- although sometimes, this is not the best thing to do. If you rescued the tadpoles from a swimming pool or flooded curb or from a stream that has since been polluted or developed over, then you need to find someplace else nearby to release the frogs. Choosing the best release site depends on the species of frog you have. Refer to a frog guide and see what is described for the habitat of your species. Then look for a site that matches that description.
The best time to release tadpoles is on cloudy/rainy days or late afternoons so that the sun is not too strong, the temps are starting to cool but there is still enough light for the tadpoles to move around and choose hiding spots.
The tadpoles are dying -- what's wrong?
If you find that large numbers of tadpoles are dying in your containers, then something is wrong. Use this checklist to see if something needs to be fixed:
- Is the water clear or is it starting to go 'off'? Have you done an ammonia test?
- Has anyone put their hands in the water in the last 24 hours?
- Have any cane toads gotten into the container?
- Have any chemicals splashed into the water?
- Has anyone sprayed any room fresheners, carpet cleaners, bug sprays or other aerosols nearby?
- What sort of water did you use? Was it fluoridated tap water or water with algae in it?
- Did you use an old container of fish food (which might have gone mouldy)?
- Did you wash the lettuce leaves thoroughly before freezing?
- Is there enough oxygen in the water? Do the tadpoles spend any time hanging vertically from the water's surface? If yes, this means there's not enough oxygen.
- Are the tadpoles growing at very erratic rates - some are getting big while many others are still the same size they were when they were a week old? (This usually shows they are too overcrowded in the container.)
- Is the container getting too much sun? Adding an aquarium thermometer will help you monitor the temperature - above 32 degrees celsius it too high! 27 C is a good temperature.
- Are the tadpole deaths occuring at different times during their growth or are all the deaths occuring at very specific stages such as when rear legs are just starting or the tadpoles are ready to metamorph? Are any air bubbles, crimped tails, colour shifts to very pale or very dark, shrinking bodies, twisted legs, swimming in circles or rolling upside down present? Are only a few tadpoles dying or are most of them dying?
- Are the tadpoles okay while all the deaths are occuring only after they metamorph?
- Are the metamorphs getting enough food?
- Did you disinfect the tank and rinse it thoroughly since you used it for the previous batch of tadpoles? Was the frog tank disinfected and rinsed well before the metamorphs were set up in it?
- Was the bucket you used to refill their tank used for any cleaning products?
If you are in Australia and you are having problems with your tadpoles that can't be fixed by the checklist above, then please contact us to discuss it. If you live in FNQ, we might ask you to give us the remaining live tadpoles so that we can raise them ourselves to try to determine what the problem might be. If you are overseas, you need to find someone local to help you. Phone your nearest Fish and Wildlife office or a university that has a vet school or biology department to ask what labs are nearby to do disease testing.
There are many details to cover when setting up tadpoles in containers, but if these are done properly, raising tadpoles will be very easy and not take up very much of your time. It's only when the setup is wrong that a lot of labour comes into it. Good luck with your tadpoles and enjoy the experience!
Tadpole keeping in Queensland
Rescuing tadpoles is very important to frog conservation but there are laws which can be used to prevent you from keeping tadpoles if you do not take the right steps to ensure mozzies can't reproduce. There are two government agencies which are involved in visiting properties to inspect for mozzie breeding sites. They can issue you with a warning and you can be prosecuted if you do not comply with the warning.
The first one is the Tropical Public Health Unit in Cairns (phone 4050-3600). They only inspect properties when a case of Dengue has been reported in the immediate vicinity such as a near neighbour. They are only concerned with the breeding of mozzies which are known to carry a disease and they can provide information and advice to you so that you know what needs to be done around your property to stop disease-carrying mozzies from breeding. They can identify mozzie species and they are also experimenting with various types of mozzie-specific baits which will trap mozzies without interfering with the environment otherwise.
The second department which can show up on any property is your local council (e.g., Cairns Regional Council) and their inspectors will be looking for breeding sites for ANY mosquito species - not just the disease causing ones. If you are found to have any mozzie breeding sites on your property, council can issue you with a notice under the QLD Health Act.
We have received some complaints from Cairns residents who have expressed concern about what is happening on their properties when they are not home and who have been ordered to get rid of their tadpoles. Residents have come home to find bird baths tipped upside down, or been alone at the back of the property only to turn around and have council staff standing behind them! In one case, we were informed that council staff dumped out a tank full of rescued frog tadpoles while the homeowner was at work. We contacted Cairns Council to enquire about normal procedures for mozzie inspections. We were told the following:
- Cairns City Council inspectors do NOT have the authority to wander around your property if you are not home. They are allowed to walk up to the front door and knock - if no-one is home, they are supposed to leave a notice in your letterbox for you to contact them.
- Council inspectors are NOT supposed to interfere with items on your property. If a breach is found, they are supposed to issue you with a warning to comply.
- Council inspectors will have clearly visible photographic ID badges and will be wearing tan jumpsuits with the CRC logo embroidered on them.
- Council inspectors are supposed to be knowledgable about how to keep tadpoles without breeding mozzies and should be prepared to discuss your tanks and ponds with you if they feel you are not taking sufficient action to avoid mozzie breeding.
Both the TPH Unit and council inspectors can order you to get rid of your tadpoles but they CANNOT dump out a tank or pond of tadpoles themselves (frogs are protected so this would be a violation of the Nature Conservation Act). If this should happen on your property, you should lodge a complaint immediately with proof of who disposed of the tadpoles (you'll probably get a warning notice). The complaint would go to QPWS, Building 2, 5B Sheridan Street, Cairns, 4870. If you are home when the inspection takes place and, if there are any dispute issues, you should get the names of the inspectors and phone the relevant agency to discuss the items of dispute.
If you are taking the correct steps to prevent mozzie breeding in your tadpole enclosures, then there are no grounds for either agency to force you to get rid of your rescued tadpoles. The steps you can take to keep your tadpoles and comply with the QLD Health Act are:
- The most effective and least labourious method is to have small fish in the enclosure; natives are better but guppies will do (before you source your fish, see the Pond considerations page for information about fluoridation and small fish). Pacific Blue-eyes are a lovely native fish from FNQ but be aware that they are sensitive to change and must be introduced to the tadpole enclosure according to proper aquarium procedures (keep fish in bag and hang over side; once an hour, take out a cup of water and add a cup of water from the enclosure, etc. - ask the aquarium shop staff to show you how). Mozzies produce a lot of eggs so if you are using guppies, add one guppy for every five to seven litres of water in the enclosure; try half that number of Blue-eyes and increase if they can't keep up with the mozzie numbers. If you add too many fish, they might start eating the tadpoles so only use the minimum number of fish to eliminate the mozzies.
- You can also use tight fitting covers on tanks to prevent mozzie access but they must be fitted tightly to the lids. Sunlight is needed during the day so we surround the tanks with some mozzie coils and clear the zone first; then we take the covers off and replace them before the coils run out. We use chiffon fabric which is sheer and fine and lets lots of air and light through. We keep the fabric stretched taught over the tops of the tanks by cutting lengths of elastic (from the fabric shop) and tying knots in them so they stretch tightly around the rim of the tank. There is also a fine flyscreen netting available at Geo Pickers which has been recommended but we haven't tried it yet ourselves.
- Other garden items can be sources of mozzie breeding as well such as glogged gutters, bromeliads (there is a debate on this but be aware), and plant cuttings you are trying to strike. Many brom growers believe that the plants excrete a chemical which prevents mozzies using the water in the centre stem but the researchers dispute this and point to published papers on the testing that has been done on broms. A small drop of vegetable oil in the centre of each plant will create a film that prevents reproduction but we don't know what this might do to a frog's porous skin. Flushing the centres with the hose still seems to be the slightly more desirable option if you have small frogs in your yard. If you use the oil option, it needs to be a very light oil so that it spreads over the water's surface. A heavy oil will form a ball and sink. Methoprene is also available to do basically the same thing but this is a chemical in the "endocrine disruptor" group so we are reluctant to promote its use if frogs are present on the property. (Please note that dengue inspectors also use methoprene pellets to toss into gutters and water bodies so please discuss other options if they want to use these pellets on your frog property.)
- Gutters need to be kept cleared and plant cuttings can be placed in bottles with narrow necks such as soft drink bottles. Use cotton wool or aquarium wool stuffed into the neck to prevent mozzies accessing the inside of the bottle.
- There is a red wriggler which also finds its way into tanks, especially if you have sand in the bottom, and these are nothing to worry about as far as the legislation is concerned. They are midges (sand flies), they are not a mozzie and they do not carry any diseases (well, not any diseases that are of concern to the authorities). The fish should love them.
- Dengue mozzies in particular will breed throughout the dry season and they have a preference for the colour black - start changing over your potted plants to other brighter colours or terra cotta and avoid the cheap black plastic pots and dishes.
If you have been inspected and ordered to remove your tadpole enclosures, please contact us. We can advise you where to release the tads or we might take them ourselves to complete their rescue and development.