Your pet chameleon has limited abilities when it comes to communicating with you. Hissing is his way of expressing displeasure with something in his environment. A hissing chameleon may become aggressive if he continues to feel threatened, so try to calm him down if he begins hissing at something while you are interacting with him.
Stress and Your Chameleon
Stress can be a major factor in your pet chameleon's health. A chameleon who is under a significant amount of stress may have a shortened lifespan and die earlier than a chameleon who is not. Hissing is a sign that your chameleon is unhappy and stressed out. A variety of experiences can cause your chameleon to hiss, especially if your chameleon is not particularly tame. Potential stressors can include an intruder (human or animal) in his environment, an unfamiliar item in his environment or illness.
Calming Your Chameleon
Calming your chameleon and removing the causes of his stress from his environment can help stop the hissing and keep your pet healthier long-term. To calm your hissing chameleon, stop whatever you were doing that made the chameleon hiss in the first place. If your chameleon is hissing at another animal or object that entered his environment, then calm him down by removing the offending creature or object.
Check The Environment
Chameleons in glass enclosures often hiss if they see their reflections in the glass and mistake their own reflection for an intruder. If your chameleon seems constantly bothered by this, consider switching him to a non-reflective cage. Some chameleons may also hiss or appear unhappy if the room temperature is not right, if they are mating or breeding or if something in their general environment is amiss. Sickness can also cause your chameleon to hiss. If you cannot find an external cause for your chameleon's stress, then take him to the veterinarian to be checked out.
Taming Your Chameleon
Some chameleons hiss at people because they were never tamed properly and do not want to be handled or have their territory invaded by humans. If your chameleon does not like people, there is a chance he was never tamed correctly. Spend a small amount of time each day working with your chameleon in a positive, stress-free manner. Spend time just sitting near his cage, talking to him. If he accepts your presence then you can try placing your hands in his cage or offering him small treats. Continue making gradual progress until your chameleon no longer views you as a threat. Keep your chameleon calm while you work with him. Back off if he starts hissing at you.