Those sound like stress colors to me. What type of setup is he in? How long have you had him (it could take a while for him to get used to the new home).
Do you have him in a high traffic part of the house? Any other pets (like cats) visiting him?
Remember that chams are solitary animals that like to be left alone. That mean no glass or other materials that may give a reflection (but I don't think that is as big of a problem until they are 5-6 months old).
>>Thanks guys. As you can probably see I am complitely new to cham and from my observation he only opens this mouth when sitting close to the lamp. Do you know by any chance when do chameleon normaly start showing their natural colore, my is only 3 month old and keep brown colore with green mix but sometimes show black?
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1.0 Bearded Dragon (Charlie)
0.1 Corn Snake (Diamond)
1.1 Felines (Blacky and Princes)
1.0 Canine (Skeeter)
2.0 Cockatiels