Why Is My Iguana Turning Black? {6 Common Reasons Explained}

A few days back my green iguana turned completely black all over and it gave me a bit of a shock. I was left wondering why is my iguana turning black?

Are they ill? Is it normal? should I do something?

Well it turned out my iguana was ok and was nothing much to worry about, but an iguana turning black can also be a sign something serious is happening.

Why Is My Iguana Turning Black?

The most likely cause for your iguana turning black is because they are suffering with stress.

The 6 common reasons include:

  1. Stressed
  2. Too Cold
  3. Scared
  4. Shedding 
  5. Angry
  6. Illness

If your iguana is suffering with one of the above conditions you will want to resolve the issue as soon as you can to prevent the iguana from becoming sick.

It is normal for an Iguana to change to a black or grey color once every few weeks for a few hours, But if they are changing more often then you will most likely need to address the root cause.

Below is a pic of what my Iguana looks like before their head turned black.

Iguanas Turning Black

What To Do When Iguana Head Turned Black

If your Iguanas head is frequently turning black or a grey colour then you need to find the root cause and fix it before the condition gets worse.

Listed below are the most common issues and how to resolve them.

1. Stress

Stress is the most likely cause and can some times be quite hard to track down what is causing the issue.If your Iguana is suffering with stress their head will turn darker first before spreading to their body.

Make sure they are warm enough, not scared or angry and not ill (All points covered below)Also are you feeding them a balanced diet once a day.  It is possible they are either hungry or being over fed.

Are they comfortable in their environment, is there enough space for them?  Some iguanas can be fussy about the floor in their enclosure, I recommend you use reptile carpet (Link to Amazon) which they seem to like the most.

Is there shade in their environment? It can be that they are to hot and want to cool down.  Make sure there are a few locations they can escape out of the heat from.

The below video will give you more information about stress in Iguanas:

YouTube video

2. Too Cold

Your Iguana will become stressed if they become to cold.  They require a heat lamp to be on around 10 hours a day.  They do not need the heat lamp on all the time as long as the temperature does not fall below 16c.

The most obvious sign that they are cold is that they move around very slowly and tend to not move a lot less then normal.

Also if the whole body turns darker or a black hue it is a sign your iguana is cold and is turning dark in an attempt to soak up more heat.

They require constant heat even through night time, but they need complete darkness so you can use a ceramic heat emitter to keep them warm.

I recommend to place a thermometer in the enclosure that they are in so you can monitor the temperature and check this article that will help you.

iguana with dog

3. Scared

If an Iguana is scared they will let you know by changing the colour of their head.

If the Iguana is new to the environment then they need some time to settle, The same is also true if you have just changed their environment around.

An external factor can also be causing the issue such as other pets and even something it saw out of the window.  If they are located near a window try to move them for a few days to see if this helps.

If they are scared be careful when handling them as they might try to bite you.

4. Shedding

An adult iguana will shed its skin roughly once a year, during this time their skin will change colour to a darker / grey colour.  Look out for patches of colour on your iguana as this will be where the skin has come off showing the skin underneath.

The signs to look out for that your iguana is going to shed are

  1. Skin changes to a darker / grey colour
  2. White patches / spots will appear on the skin
  3. The skin usually starts to come of around the head and hands first
  4. They might become lethargic
  5. Stop eating for a few days

You can help the shedding process by soaking them in water or spraying water over their body.

5. Angry

The most common reason for an Iguana showing aggression is because they are in season or are pregnant.  At this time it is best to keep your distance from them and give them their space.

Also an untamed Iguana will show aggression towards you until they feel safe with you and trust you.

They can also show signs of aggression when other pets are around them.

Sometimes they are reacting to toxic food they ate. More on that here.

6. Illness

If your iguana is ill it should be easy to spot.  Look out for these signs:

  • Not Eating : This is the easiest thing to check, it is normal for them to go one day with out eating, but if they have gone two or three days they might be ill.
  • Not Moving : If they are not moving or moving around very slowly they could be either cold or ill.
  • Not Walking Strait : They could be dizzy or feeling weak which is causing them to have issues to walk properly
  • Vomiting : If they vomit more than once you should take them to a vet.
  • Infection: For much more information on this, please visit my other article here. 

Frequently Asked Questions:

Below are some frequently asked questions about this topic.

1. Go Iguanas Get Darker As They Age?

Yes, A typical iguana will start out a bright blue or green when they are a baby and will naturally lose the bright colour and become slightly darker as they age.

2. Do Iguanas Change Colour To Camouflage?

No iguanas are unable to change their colour by themselves.  They will only change colour if there is an issue such as they are stressed, to cold, shedding or are ill.

3. Do Iguanas Change Colour Like Chameleons?

No, Iguanas are not capable of changing their colour to blend in with their background.


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My name is Anna and I work full time in my local pet shop where we sell many animals that I write about on this site. I love all animals and love writing about them.