FAQ: Heating & Lighting for reptiles

Yes, tortoises need UVB for shell and bone development, because without it calcium is not absorbed. Indoors the UVB lamp should cover the basking spot, and in warm weather time in a safe outdoor pen in direct sun is beneficial.

Yes, sliders and other aquatic turtles need a UVB lamp over the basking platform for a healthy shell. The lamp should be at a height where the turtle gets proper UVB when it climbs out, but cannot reach or splash it.

No, ordinary glass and most plastics block almost all UVB, so the lamp must shine straight into the terrarium or through a metal mesh. For the same reason, a reptile kept by a window does not get UVB from the sun.

A metal mesh blocks part of the UVB, and how much depends on the hole size and wire thickness; a fine mesh can cut output considerably. That is why a stronger lamp is often chosen when shining through mesh, or the lamp is mounted inside the terrarium with a guard.

UVB lamps weaken over time even though the visible light looks the same. They are usually replaced every 6–12 months depending on the type and the manufacturer’s guidance; a UV meter gives a more precise picture.

A lamp’s UVB output drops much faster than its visible light, so a lamp that still shines may be giving off almost no UVB. If it is not replaced in time, the reptile may gradually not get enough vitamin D3.

A UV meter shows how much UVB actually reaches the reptile’s basking spot, so it helps set the right lamp height and tells you when to replace it. It is especially useful for more demanding species or when keeping several terrariums.

Compact UVB bulbs give off UVB over a narrower area and a short distance, so they suit small terrariums or species that need little UVB. For large terrariums and desert lizards a long tube covering more of the terrarium usually works better.

A UVB tube should usually cover roughly half to two-thirds of the terrarium’s length, so the bright UVB zone is wide enough while the other end stays shaded. Choose a length that fits the terrarium lid or interior alongside the basking lamp.

Fluorescent UVB tubes need a fixture with a ballast that keeps them running evenly. An electronic ballast lets the lamp shine without flicker and usually extends its life, and the fixture must match the tube type and length.

A reflector directs most of the UVB downward, so output can rise several times compared with a bare tube. Because of this, a lamp with a reflector often has to be mounted higher so the reptile does not get too much UVB.

Yes, a UVB lamp that is too close or too strong can irritate a reptile’s eyes and skin. That is why it is important to follow the manufacturer’s distances, leave a shaded zone in the terrarium and talk to a vet if the reptile squints or avoids the light.

For some nocturnal species vitamin D3 in food partly makes up for missing UVB, but for diurnal lizards and turtles it does not replace the lamp. Supplements must be balanced carefully because an excess is also harmful, so ask a vet about them.

The UVB lamp is usually installed on the same side as the basking lamp, because in nature reptiles get UVB while basking in the sun. That way the reptile gets UVB while warming up and can rest in the shade on the cooler side.

Yes, UVB and lighting lamps are most conveniently run on a timer so the day length is the same every day. UVB usually runs as long as the basking lamp, about 10–14 hours depending on the species and season.

A ceramic heat emitter screws into a socket like a bulb but gives off only heat, no light. It suits night-time heating or species that need extra warmth without bright light, and it must always be run through a thermostat.

The wattage is chosen by the terrarium volume, the room temperature and how many degrees the temperature needs to rise. It is better to pick a slightly stronger heater controlled by a thermostat than one too weak to warm the terrarium on a cold night.

A ceramic heat emitter runs at a high surface temperature, so touching it can cause a severe burn. It must be fitted in a ceramic socket, covered with a mesh guard and kept away from decorations and the terrarium walls.

Since a ceramic heat emitter does not glow, its operation is best checked with a thermometer or an infrared thermometer measuring the temperature beneath it. A thermostat with an indicator light showing when the heater is on is handy.

Any heater that warms the air lowers the relative humidity, and a ceramic heater does so quite strongly. For tropical species this can become a problem, so watch the hygrometer and mist more often if needed, or choose another heating method.