Lighting Your Turtle Habitat
The lighting in a turtle habitat is very important. The lights aren't just there so we can see our turtles. It's much more important than that.
Without the proper lighting, our turtles will get very sick and eventually die.
Aquatic turtles need two kinds of light: Light that approximates normal sunlight, which should be placed over their basking area; and UVB (Ultraviolet B) light.
Turtles also need to have "days" and "nights," just like people do. Without day and night cycles, your turtle's sleep habits will be disrupted, causing stress and possibly reducing your turtle's immunity and overall health.
Let's talk about UVB light first because it's the area where most new turtle hobbyists make mistakes.
Why Do Turtles need UVB Light?
Turtles (and all reptiles) need UVB light to produce Vitamin D3, and to help them properly use calcium and other nutrients. Without enough UVB light, turtles will experience shell problems and metabolic bone disease, and probably will die. It really is that important. If you can't afford to buy a UVB lamp, then please don't get a turtle until you can.
Sadly, the main reason that many captive turtles don't have enough UVB light is not because their keepers can't afford one. It's because their owners simply don't know that their turtles need UVB. This is especially true when people get a baby turtle at a carnival or a fair without planning for it in advance. Many of these baby turtles will die in less than a year because their owners simply didn't know how to take care of them.
That's why we're glad that you're not like that. You're reading this Web page because you want to know how to take proper care of your turtle. Good for you!
Lighting Up Your Turtle's Life
Luckily, it's pretty easy to give a turtle all the UVB light it needs. In fact, you can satisfy all of your turtle's light needs with one lamp, if you like. There are lamps called "Self-Ballasted Mercury Vapor Lamps" that provide heat, daylight, and UVB all in one lamp. They're an excellent choice if you don't have a lot of room or if you want to keep things simple. But they're also very expensive, and they shouldn't be used on small habitats because they provide very intense light.
Most people choose to use two lamps, usually a fluorescent UVB light and a separate basking spotlight. UVB fluorescent lights are available in either tube or compact designs, in different lengths and intensities. For aquatic turtles, most experts recommend using a 2.5 percent or 5 percent UVB lamp. These lamps are often called "Tropical UVB" lamps, and are the type you should use for aquatic turtles. Don't use "Desert UVB" lamps, which are made for desert-dwelling reptiles.
When using any UVB lamp, it's important to place it at the right distance that the turtle will get the right amount of UVB light. Usually this is about 12 inches for a UVB 2.5 lamp and about 18 inches for a UVB 5 lamp. The companies that make these lamps usually have excellent information on their Web sites that provide detailed information.
Please note that UVB light doesn't penetrate glass or plastic very well, so don't use a glass or plastic cover on your turtle habitat. Use a metal screen cover instead. You also can use no cover at all, but this can be dangerous. Lamps occasionally explode when they get splashed by water, and the glass can injure your turtle.
Compact vs. Tubular (Linear) UVB Lamps
UVB fluorescent lamps are available in two styles: Tubular (sometimes called Linear), which are straight and come in various lengths for different size fixtures; and Compact (shown on the right), which usually are squiggly-shaped and screw into a regular light socket. When the compact UVB lamps first came out, there were a lot of problems with them. Some of them didn't generate enough UVB light, and others seemed to generate too much. Some of them also seemed to irritate turtles' eyes.
The companies that made these lights went back to the drawing board and re-designed them, and many turtle experts believe that the problems have been fixed. But others still don't trust compact UVB lamps and won't use them. One thing that most experts agree about, however, is that if you choose to use a coil-type YVB lamp, you shouldn't use a shiny metal reflector with it. That concentrates the UVB light too much. Use a fixture with a dull or painted interior, not a shiny metal one. And if your turtle shows any sign of eye irritation (for example, if it gets puffy eyes or stops basking), then turn off the coil light for a few days and see if it clears up.
The other kind of light that turtles must have is a basking spotlight, sometimes called a "Daylight" lamp. These lights are usually incandescent lamps that screw into an ordinary light socket, and they produce heat as well as light. Some of them, like the one on the right, have built-in reflectors that focus the beam. Others are round like a regular light bulb and should be used with a reflector (the next picture down on this page).
Basking lights should be aimed at a part of the turtle's basking area and placed at a distance that heats that spot to the high end of your turtle's temperature range. For most adult aquatic turtles, this temperature should be about 87 - 92 degrees Fahrenheit. For babies and turtles who are sick, it should be closer to the mid-90's Fahrenheit.
Don't guess about basking light placement! Use a thermometer instead. They are available in the reptile section of pet stores, and are not expensive. If you place your basking lamp too far away, your turtle can catch a chill and come down with an RI (respiratory infection), which often is fatal to turtles. If you place it too close, you can burn your turtle. So don't guess about the temperature. Be smart and use a thermometer.
Notice that I said earlier to aim the basking light at a part of your turtle's basking area. That's because ideally, you want to produce a range of basking temperature. The hottest place -- right where the light is pointed -- should be the high end of the range for your turtle specie (usually about 87 degrees Fahrenheit). The coolest part of the basking area should be at the low end of the temperature range (usually around 82 degrees Fahrenheit). By creating a range, you're giving your turtle a way to regulate its body temperature by moving from one spot on the basking area to another.
When taking temperatures, take them with the tank cover or screen in its usual position. Tank covers affect how much light and heat get through. When you remove the tank cover (for example, to feed the turtles or work on the habitat), put it back as soon as possible so the tank doesn't overheat. If you must leave it off for more than a few minutes, then turn off any heat-producing lamps or move them farther away to prevent overheating.
A third kind of light that many people like to use is called a "nocturnal viewing lamp," or simply a "night light." These usually come in either red or purplish-blue ("black lights") and are designed to allow night viewing without keeping your turtles awake all night. They also generate some heat (especially the red ones), which helps keep your turtle's land area warm. This is mainly important for hatchlings; adult and older juvenile turtles usually sleep in the water.
If you decide to use a night light, be careful with it. Some of these lamps put out a lot of heat and can burn your turtle if you place them too close. As for the choice of color, it's pretty much up to you and your turtles. I've noticed that some turtles seem to be kept awake by red lights, while others don't seem to care.
Circadian rhythm is just a fancy name for the normal 24-hour cycle that most living things need to thrive. Like almost all animals, turtles' focus their energy on different things at different times during a 24-hour day. This is true on the biochemical level, not just in terms of their behavior.
It's important that a turtle's habitat include day and night cycles. The natural rising and setting of the sun does this for turtles who live outside in ponds. But for turtles kept indoors in tanks, we have to create their days and nights by turning the lights on and off. In general, the "daytime" lights (that is, the basking and UVB lights) should only be kept on for 10 - 12 hours a day to mimic springtime, or 12-14 days to mimic summer. When the daytime light is not on, either no light or a night light should be used.
An automatic timer to turn the lights on and off is a good investment for your turtle habitat. These timers can be purchased at pet shops or at home supply companies, and are not very expensive.