Frogs are fascinating amphibians which are increasingly being kept as pets by enthusiastic herpetoculturists. Caring for frogs in captivity naturally results in a desire to have a go at breeding them, providing other frog-keepers with captive born stock, making some money to recover the costs of buying the animals and equipment, and an amazing opportunity of observing the amphibian life cycle from egg to frog. Any successful frog breeding project must include research about, and a plan of how to raise the tadpoles.
Tadpoles are the larval form of frogs. The vast majority of amphibian species reproduce through externally developing eggs which result in aquatic tadpoles, and after a period of growth, undergo metamorphosis, which completely changes their morphology to froglets, which can live on both land and water. Because of the huge variety of types of frog that are bred in captivity, this article will not be able to provide detailed information about raising tadpoles of a specific species, but will discuss some universal considerations that are applicable to all tadpoles.
The vast majority of frog species start their life cycle as complete aquatic larvae, making the care of tadpoles is not dissimilar to that of aquarium fish and fish fry. Once the eggs are laid by the female they should be removed from the frog terrarium and placed in their own aquarium. The water in which the tadpoles will be reared must be dechlorinated, the easiest way to achieve that is by treating tap water with an aquarium fish water conditioner, which removes chlorines and chloramines. The water should be maintained at a temperature that is specific for the particular species of frog that you are breading, which might necessitate adding a heater to the aquarium.
It is best not to use gravel in the tadpole rearing tank, since it makes cleaning easier. Initially no filtration or aeration should be used, since the tiny tadpoles will find it hard to swim against the currents created and could be sucked up into the filter. It is easiest to start with a low water level, and gradually increase it by adding more dechlorinated water at the same temperature as the tank water, since water changes with tiny tadpoles are difficult. As the tadpoles grow in size and the rearing tank becomes filled with water, daily water changes of 50% of the water will become necessary to keep the water quality high. Gentle aeration with an airstone and an air pump should be added about 2 weeks after spawning. Biological filtration may be added using a simple sponge box filter driven by an air pump.
Feeding strategies for the tadpoles will depend on their species, and should be researched for each species that is raised. During the first few days after hatching, the embryos will not require food, since they will be absorbing their yolk sac. It is however preferable to start feeding too early, rather than too late, since starvation at this early stage in development can seriously delay growth and might lead to developmental abnormalities. Many frog species are herbivorous during their larval stages and can be fed on lettuce and other greens, which should be blanched under boiling water to soften them. Tadpoles of the African clawed frog are basically filter feeders and should be raised on infusoria, or powdered algae tablets. Providing some light over the tadpole tank will encourage the growth of algae and green water, providing a non-polluting and self-sustaining source of food. Carnivorous tadpoles such as those of the horned frogs, are perhaps the most difficult to feed, since they need live food and would probably do best on fish fry. They are often cannibalistic and will require isolating as they grow.