Although crested geckos make good pets, they dislike being handled. When handled, a crested gecko can bite, however, their bite seldom causes serious injury. The bite of a crested gecko may startle you at first, but it will not harm you. A bite from a crested gecko, on the other hand, can result in the transmission of bacteria and some fungi. Because bacteria and fungi can be toxic, it is best to wash your hands after touching and biting a crested gecko.