JD by nature is a timid cichlids, and the larger they grow , the more skirmish they become. The only time they are bold is when they are juvies, coming out to greet and beg for food. The same behavior is also observed in the wild, as divers have observed bold juvies and shy adults. I have raised JD a few time and they all get shyer with age. Other CA that are even more skittish are Viega species. They were so shy to the point that I have to approach the tank slowly or else they would jump and bump their head. I guess the only way to calm them is to keep many of them in a huge tank when they pay more attention to one another than feeling the lone target of attention. Smaller convict cichlid or African cichlid, on the other hand, are never shy but they are always kept in a group.
There are tank busters that are always bold such as Dovii, Jaguar, red devil and hybrid Flowerhown, and they are often kept as wet pet.