Many owners become seriously confused and worried when their leopard gecko starts turning brown/dark. But why is a leopard gecko turning brown? In this post, we will discuss the reasons why a leopard gecko is turning brown and what you can do to resolve it.
Reason number 1: Your leopard gecko is cold
Your leopard gecko might be turning brown because it is cold inside or outside the tank. Turning brown/blacks helps absorb as much heat as possible.
Make sure to have ideal temperatures inside your leopard gecko’s vivarium. The warm side should be 83-90 degrees F (28-32.2 Celsius) and the cooler side – 70-77 degrees Fahrenheit (21.1-25 Celsius) during the day.
During the night, don’t go lower than 66 degrees (18.8 Celsius), and it is better to keep the night time temperatures in the range of 70-74 F (21-23.3 Celsius).
It is also important to have a temperature gradient in the tank – one side should be warm and other side should be cool. This will allow your leopard gecko to move to a warmer spot to warm up.
Make sure to place two digital thermometers like these on the wall, near the floor of both warm and cool sides of the tank. It is important to check temperatures near the floor, because your leopard gecko needs to heat its belly to digest food.
Don’t forget to place a warm hideout near basking lights, to let your leopard gecko hide from light if needed.
Leopard geckos tend to be their brightest color when they are heating up. Also, if the tank is very humid, or if your leopard gecko spend a lot of time in its hide, it can turn darker. Read everything about lighting and heating in a leopard gecko’s tank in this post.
Reason number 2: Your leopard gecko is shedding
Your leopard gecko might be turning brown/dark before shedding. Leopard geckos shed quite often, around once 2-4 weeks. A leopard gecko can also turn a bit gray before shedding.
This is normal, and should pass after the shedding has been finished. Don’t worry even if your leopard gecko has never been so dark before shedding in the past.
It can sometimes take 5-7 days for your leopard gecko to shed fully since it has become dark. If your leopard gecko doesn’t go back to normal after shedding, then there might be another reason for this.
Reason number 3: Your baby leopard gecko is changing colors/patterns
It is not uncommon to see leopard geckos change colors as their grow older. Leopard geckos can change colors up to until 12-18 months of age.
Some leopard gecko morphs, such as Carrot Tails, Patternless and other bright yellow and orange morphs, tend to become darker or lose their markings after 1-3 years of their life.
Most leopard geckos will develop their markings fully as they grow older, and there can be darkening of stripes.
Reason number 4: Your leopard gecko is stressed/moody
Sometimes, leopard geckos might become darker when stressed. Stress might be caused by many things, such as wrong temperatures, lighting, diet, substrate, tank sizes, handling and so on. Try to work out what could be wrong and change it.
Make sure temperatures are ideal during the day and night, in the cool and warm spot, and that there is a temperature gradient. At night, use bulbs that won’t disturb your leopard gecko’s sleep (for example this ceramic heat emitting bulb). Leopard geckos can see colors, so using white/red/blue bulb is not the best choice.
The temperature in the vivarium should drop at night, so using bulbs is not always necessary. You can also use an under tank heating pad instead of bulbs to heat the tank at night.
Make sure that the mat is not bigger than 30% of the tank’s size, and place it on one side to create a temperature gradient. Small heating 8″x6″mat should be ideal for a 10-20 gallon tank. Your leopard gecko can turn brown even when the temperature in the cool spot is too high.
If your leopard gecko’s tank is 2 ft, using bulbs might be problematic, as it can get too hot in a cool side of the terrarium. An under tank heating pad and a low wattage daylight bulb is a better choice in this case.
Generally, leopard gecko don’t need UVB lighting if your provide them with vitamin D3. While you can use a fixture or bulbs that emits 2-5% UVB, this is not necessary if your supplement the diet.
If you don’t gut-load and dust the crickets and other feeder insects with multivitamins, calcium and vitamin D3, your leopard gecko will not only become darker, but develop deficiencies. Read about the best supplements and supplementation here.
Reason number 5: The substrate in leopard gecko’s tank is turning it brown
Some substrates can make your leopard gecko appear brown. These are substrates that are especially darker such as coco fiber and dark sand.
While it doesn’t happen with all leopard geckos, this kind of substrate can also be linked to higher humidity that makes your gecko appear duller. For example, coco fiber needs to be sprayed with water and it can increase the humidity in the tank.
In general, you should not use any loose substrate because the impaction risk is too high. The worst offenders are sand and pebbles, but coco fiber can also cause impaction.
Sphagnum moss or vermiculite should not be used in a whole tank, as they increase the humidity in the tank greatly. Only use them in a shedding box for your leopard gecko.
Read about substrate choices for your leopard gecko in this post.