Why is my blue iguana's back turning orange-brown? Is it serious?

Check the basking temperature and temps on the cool and warm sides. The darkening color may be due to low temps. An iguana will darken, when necessary, to absorb the maximum amount of available heat. The link below has an incredible amount of information regarding all aspects of keeping iguanas. http://www.anapsid.org/iguana/index.html

It is difficult to appreciate the red spots in the images provided. Monitor for lethargy, decreased appetite or spreading of the spots. Clean and sanitize the cage, bowls and hides. Use paper towels as substrate and change it daily. If Beast develops any of the above symptoms, have him examined by your veterinarian or a vet experienced in treating reptiles to diagnose and treat illness or injury.

It could be a hard shed or local infection (bacterial or fungal). Soak or mist him with warm water. Cleanse the area with diluted betadine or chlorhexidine solution daily. If the spot doesn't resolve or spreads, have him examined by your veterinarian or an experienced herp vet.

Without an image or physical exam, it can be difficult to determine exactly what is going on. It could be a bacterial or fungal infection, skin from shedding or trauma (burn, abrasion, etc). Ideally, Iggy should be examined by your veterinarian or a vet experienced in treating reptiles. You can find one using the link below if necessary. http://arav.site-ym.com/search/custom.asp?id=3661 In the meantime, confirm proper environmental parameters. To much humidity can promote bacterial or fungal overgrowth, too little humidity can lead to difficult sheds. Make sure Iggy cannot come into contact with either the heat lamp or UVB light source. Minor infection can be treated with daily cleanings using diluted Betadine or Chlorhexidine. Clean and sanitize the cage and use plain paper towels as substrate to make cleaning easier until the issue is resolved.

Yes, your Iguana is probably sick but these symptoms are very general and i couldn't tell you what is causing this, you will need to take him to an exotic vet specialist ASAP in order to get him checked.

Thanks for reaching out about Rango and including a photo. By the picture, could these be on the surface of the skin, do they scratch off? Melanin pigments are often the result of a trauma to the skin. This darkening will often go away once the insult if removed. Insults could be sharp bark, mites, infections and more. If the problems progresses, a veterinary visit is recommended to assess and provide a diagnostic/treatment plan. Try giving a bath in clean water. Good luck.

I'm sorry Poseidon is having some problems with his scales. The blackening may be caused by a fungal or bacterial infection. This typically requires changes to the husbandry along with a topical antibiotic or anti-fungal. It is best to have him seen by an exotic vet who can prescribe the appropriate medication. We cannot determine whether or not his normal scaling will return. Scarring will prevent the scales from coming back normally so it is best to address this issue before it worsens.