my jackson chameleon died about 9 months ago he was doing great than one day he was black in the stomach and in is eyes were also black the eyes also sunken in, he was compeletly fine when i checked on him than i watched a movie and i came up he was like that, i think he may have eaten some moss...
that sounds right they might not get there adult color until they are six months old
here is a younger chameleon i had that might be around 5 months
he may not be that old, though you may won't to show us photo of him:cool: