Your amphibian will thrive best in an environment that closely resembles its natural habitat. This habitat should provide your pet with the adequate temperature ranges (to digest food and fight disease), the correct light and dark periods (to hunt for food and maintain biorhythms), and the sufficient amount of moisture (to shed). It will be easiest to achieve this delicate balance by setting up your vivarium well in advance of your new pet's arrival.
Ambient and Gradient Temperatures
Amphibians, members of the herp group, are cold-blooded animals and therefore unable to generate body heat. They require a slight increase in temperature to assist in the digestion of their food. Deprived of the required heat, their ingested food could remain unabsorbed, and ultimately decompose in their stomachs. Some salamanders have the ability to regurgitate undigested food as a defense mechanism. If it seems to happen too often, consider adjusting the vivarium's temperature levels.
In setting up your amphibian's enclosure, provide a thermal gradient that will let him thermoregulate, or move between warm and cool areas on his own. Warm one end of the tank with an under-tank heating pad or basking lamp, and leave the other end cool enough for him to retreat to when he needs to chill down or sleep. If you have a semi-aquatic vivarium, you can ensure correct water temperatures with an aquatic heater.
Remember that some popular pet amphibians (especially those in the salamander group) come from very cold climates, so you need to adjust the temperatures carefully. Fire salamanders prefer ambient - or air - temperatures of 60 to 70 degrees Fahrenheit. Arboreal salamanders (Aneides) require temperatures as low as 58 to 68 degrees F, and some varieties of fire-bellied toads need a water temperature close to 64 degrees F. Exposing these species to higher temperatures will cause heat stress, which could be fatal. You will know that your pet is heat stressed if it's fretful and constantly circles the tank looking for a cool spot.
Amphibians in the wild generally experience as much as 10 to 15 degree drops in temperature during the night. These changes are part of their biorhythms and form an essential part in their feeding, reproductive, and hibernation cycles.
You will need to monitor not only the ambient daytime temperatures in your amphibian's enclosure, but the nighttime levels, too. You can install programmable thermostat controllers to automatically turn the heaters on and off for accurate temperature changes.
Most amphibians are night (nocturnal) or twilight (crepuscular) creatures - active, hunting, and feeding during the darker, cooler time of the day. They also have periods of hibernation, which are based on the turn of the seasons. It is essential, therefore, that you maintain the correct lighting periods in your pet's habitat, depending on the needs of the particular species.
In general, amphibians need 12 to 14 hours of light during summer, 10 to 11 hours during winter, and little or no lighting during hibernation.
Quality of Light
Unlike reptiles, which require full-spectrum lighting for better vision and Vitamin D synthesis, a majority of amphibians (being mostly nocturnal) have little or no need for UVB light. Based on the intensity of light they receive in their natural environments, different species will require different levels of exposure.
Some frogs and toads (and a few salamanders) will appreciate short exposures to direct sunlight, but most rainforest and dark-woods species will not be able to tolerate it. Often, situating the enclosure in a well-lit location (for example, by the window, but not under direct sun) will suffice, but low-wattage, full-spectrum fluorescent lights are ideal, especially to keep the natural plants healthy. Your landscaping will provide the necessary hiding places in case your pet prefers to stay out of the sunlight.
The moisture level of the habitat is another essential climatic requirement in the care of amphibians. Many species originate from temperate forests, which are somewhat musty, often rainy, and extremely humid. They have adapted to, and depend on, these moist conditions. Amphibians instinctively submerge in water to breed, exchange oxygen and waste gases through their pores, and sustain natural defenses through slimy toxic substances on their skin - requiring the high humidity levels of their surroundings.
You can maintain the appropriate level of humidity in your pet's enclosure through commercially available humidifiers, misters, and aeration devices. Decorative mini-waterfalls are growing more popular, not only to add interest to the vivarium set-up, but also to provide appropriate humidity levels.
But don't forget that simple creativity with basic vivarium decor can be a cost-effective solution. Aside from using a pool of water (or running water), you can add a layer of sphagnum moss to the substrate, some thick branches or stumps or pieces of cork or tree bark. Mist them daily to retain wetness, and that will take care of providing the required moisture.
Double check your pet's specific climatic requirements, because some species have extreme needs that must be uniquely addressed.