Reptile Lighting and Calcium, Explained Simply

Many of the health problems seen in pet reptiles trace back to two things: the wrong lighting and not enough calcium. Here's the short version of what you need to know. Always check the specific needs of your species.

Why UVB matters

In the wild, reptiles bask in sunlight. The UVB part of sunlight lets them make vitamin D3, which they need to absorb calcium. Without it, bones can weaken, a painful condition called metabolic bone disease.

Window glass blocks UVB, so indoor reptiles need a UVB lamp. Modern T5 high-output tubes reach further into the enclosure than older bulbs.

Replace UVB tubes on the maker's schedule, often around 12 months, even if they still light up, because UVB output fades first.

Calcium supplements

Insect-eating reptiles usually need their feeder insects dusted with calcium powder. Many keepers use a calcium with D3 at some feeds and plain calcium at others, depending on the species and the UVB set-up.

The enclosure

Choose an enclosure sized for your reptile as an adult, with a warm basking end and a cooler end so they can regulate their temperature. Front-opening doors make feeding and cleaning less stressful.

For tropical species that need humidity, a moisture-holding substrate helps.

Starter checklist