Dendrobates tinctorius morphs, and D. azureus
Dendrobates tinctorius ranges over much of north eastern South America. Populations of these frogs seem to occur in “islands” of appropriate habitat, and these populations are often separated by miles from other populations. The terrain that lies between the habitats may appear to be suitable for dart frogs, but in most cases one factor or another prevents the frogs from colonizing these areas. Factors such as seasonal inundation (flooding), rivers and other natural boundaries have kept the frog populations separated for many generations, which has led to each “island” of habitat supporting its own “morph” or color form of these frogs. There is an amazing diversity in the appearance of these frogs, and in some cases the frog populations are physically different, in particular different populations are often of different physical size.
In their native habitat, there are wet and dry seasons, and the frogs behavior varies from one season to another. During the driest parts of the year, and in dryer areas, the frogs aestivate (a form of summer hibernation), until more wet rainy weather returns. During the rainy season, the frogs can be very plentiful in their habitat, and it must truly be a sight to behold to come across a group of these frogs scattered about the forest floor.
In the terrarium the tinctorius group of frogs have always been fairly popular, and while it is a fairly easy frog to keep, many people make mistakes with this frog, particularly by keeping them in groups of their own species. D. tinctorius and azureus are the most competitive and territorial of all the larger frogs, and it is practically impossible to raise three or four of these frogs together with out one or more frogs doing poorly. This competitive nature manifests itself at a very young age, and while you will rarely actually see aggression in the younger frogs, the effects will be easily seen if you keep three or four young frogs together for a few weeks. The safest grouping is either (in order of safety!) one frog by itself, a sexed pair, or two frogs of undetermined sex. The territoriality is exacerbated by the presence of more than two frogs. However they generally will do fine with other species, so you can try mixing them with any of the larger frogs, in most cases as long as there is plenty of space and food they won't disturb the other frogs.
The territorial nature of the frogs is primarily driven by the females aggressive nature, and their drive to breed and to protect both egg laying sites, and access to males. Thus tensions are highest in tanks with two females and a male, and in such a situation the dominant female will often kill the second female within a fairly short period of time. In the wild the dominant female would drive the other female from her territory in a fairly short period of time, and the whole issue would be resolved. However in captivity, the losing female will not be able to escape, and will live under extreme stress. Stress is a major killer of dart frogs, and the source of most stress in dart frogs is their tankmates. While results will vary, a stressed out dart frog can die much more quickly than it would starve to death. I have discussed this situation in greater detail in a caresheet, which you can read here.
The tinctorius complex includes D. azureus (which for our purposes might as well be just another tinctorius morph), and all members of the group would just as happily breed with other color forms as with their own, so care must be taken not to mix the different color forms, to avoid producing crosses between the different localities. With so many beautiful creations in nature, why create confusion and potentially dilute the gene pool of these beautiful frogs by breeding one color form to another? Most breeders take great care to avoid this, and in general, you won't find reputable breeders knowingly offering these crosses. This topic is the subject of heated controversy at times, but the final argument from my point of view has always been that these frogs do not come with a pedigree or any information as to the frogs past. So while the person who produces the cross knows perfectly well what it is, and he tells the person that he sells it to, that person may give the frogs away, or breed them to each other, and at some point in a year or five, the information is lost, and they show up on the internet as the morph they most closely resemble.