What Watt Bulb is Best for a Leopard Gecko in a 20-Gallon Tank?

If you are considering bringing home a leopard gecko, it’s important to understand the temperature and lighting requirements to keep your pet healthy and happy. One of the most common questions that new leopard gecko owners ask is, what watt bulb should I use for my 20-gallon tank? In this article, we’ll cover everything you need to know about choosing the right bulb for your leopard gecko’s tank.

Why Do Leopard Geckos Need Lighting?

Leopard geckos are cold-blooded reptiles, which means they cannot regulate their body temperature like humans do. In order to stay healthy, they need a heat source to keep their body temperature within the optimal range of 88-93 degrees Fahrenheit. Additionally, they need a source of UVB light to help them synthesize vitamin D3, which is crucial for bone health.

Types of Bulbs for Leopard Gecko Tanks

There are a few different types of bulbs that are commonly used for leopard gecko tanks:

Incandescent Bulbs

Incandescent bulbs are a common choice for providing heat in a leopard gecko tank. They emit a warm, bright light and are relatively inexpensive. However, they are not the most energy-efficient option and can burn out quickly if they are not handled properly.

Ceramic Heat Emitters

Ceramic heat emitters are a type of bulb that emits heat without producing any light. They are very energy-efficient and are a good choice for providing a constant heat source in your leopard gecko’s tank. However, they do not provide any UVB light, so you will need to use a separate bulb for that purpose.

Mercury Vapor Bulbs

Mercury vapor bulbs are a type of bulb that provide both heat and UVB light. They are a good all-in-one option for leopard gecko tanks, as they provide everything your pet needs in one bulb. However, they can be expensive and can be difficult to find in some pet stores.

Choosing the Right Wattage

The wattage of your bulb will depend on the size of your tank and the temperature requirements of your leopard gecko. In general, a 20-gallon tank will require a bulb in the range of 50-75 watts. However, you should always use a thermometer to check the temperature inside the tank and adjust the wattage of your bulb accordingly.

What Watt Bulb is Best for a Leopard Gecko in a 20-Gallon Tank

Other Considerations

When choosing a bulb for your leopard gecko’s tank, there are a few other things to keep in mind:

Distance from the Bulb

It’s important to keep the bulb at the right distance from your leopard gecko’s basking spot. If the bulb is too close, it can overheat your pet and cause burns. If it’s too far away, it may not provide enough heat. In general, the bulb should be about 6-8 inches away from the basking spot.

Use a Timer

Leopard geckos need a consistent day/night cycle to maintain their health. Using a timer to turn your bulb on and off can help ensure that your pet gets the right amount of light and heat.

Replace Bulbs Regularly

Bulbs can lose their effectiveness over time, so it’s important to replace them regularly. Incandescent bulbs should be replaced every 6 months, while mercury vapor bulbs should be replaced every 9-12 months.


Choosing the right bulb for your leopard gecko’s tank is an important part of providing a healthy environment for your pet. By considering the wattage, type of bulb, and other factors, you can ensure that your leopard gecko gets everything it needs to thrive.

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