I agree with others, there is no "one size fits all" when it comes to dats. I have seen adult, single, dominant, dats, in a large mixed community remain unstable. From a previous thread on this subject....
I think that both camps are correct, that being the colors seen in a "stable" dat, and an "unstable" dat, can be caused by the same environmental triggers. Stimuli that may frighten or stress one fish, may trigger dominance or aggressive territorial behaviour in another.
The pigment cells in fish that are involved with color changes are called chromatophores. These cells can be altered due to morphological changes in the fishes environment such as background and/or substrate color, or from physiological responses to aggression, stress, etc.
In a stressed fish plasma cortisol levels increase, and cortisol levels are how researchers typically determine stress levels in fish when exposed to various conditions. Not all species, and perhaps even individual specimens within each species will react exactly the same to the same environmental or physiological stimuli.
As an example, in Nile tilapia a blue background causes an increase in aggression, where as a blue light causes a calming, protective role in stress in this species.
http://www.scielo.br/pdf/bjmbr/v34n8/4190.pdf
Fanta (16) argues that a blue background increases aggression in the Nile tilapia, and suggests that this color is not adequate for holding containers for this species. Conversely, the present data show that blue light has a protective role against stress for this same species
Hormonal color changes could explain why with an increase in age/size dats often become more stable, and tend to show what most would consider dominant coloration, vs camouflage (sub-dominant concealment) vs younger, less mature dats kept under the exact same tank conditions. In some tanks fish take on more dominant, territorial behaviour early on in life, even as small juvies, and this could also very well be sex (and hormone) related.
None of the above is outside the norm for many species of fish that are kept in captivity.
Clearly there is no question that some dats kept in a stressful environment appear to be what many refer to as "stable", displaying dominant colors, and there are dats that kept in these exact same conditions appear to be "unstable", as in displaying dark camo/concealment stress pattern & coloration.
Perhaps some fish fall under the "fight" response, and some fall under the "flight" response. Same stimuli, but opposite reaction based on size/sex/dominance/tank mates/overall health etc-etc.
IMO the reason for no real definitive answer to the "stability" question, is that no single answer is correct for all fish, of various age/size/sex, kept under all of the various conditions possible in captivity.
This is why in Indonesia hobbyists will state: That is the challenge of keeping tigers - swee swee kim kim (stable) one moment and then suddenly "orh-orh". (black/unstable)
With datnoids, this just seems to be part of the enigma and challenge that makes keeping them so interesting.
I think that both camps are correct, that being the colors seen in a "stable" dat, and an "unstable" dat, can be caused by the same environmental triggers. Stimuli that may frighten or stress one fish, may trigger dominance or aggressive territorial behaviour in another.
The pigment cells in fish that are involved with color changes are called chromatophores. These cells can be altered due to morphological changes in the fishes environment such as background and/or substrate color, or from physiological responses to aggression, stress, etc.
In a stressed fish plasma cortisol levels increase, and cortisol levels are how researchers typically determine stress levels in fish when exposed to various conditions. Not all species, and perhaps even individual specimens within each species will react exactly the same to the same environmental or physiological stimuli.
As an example, in Nile tilapia a blue background causes an increase in aggression, where as a blue light causes a calming, protective role in stress in this species.
http://www.scielo.br/pdf/bjmbr/v34n8/4190.pdf
Fanta (16) argues that a blue background increases aggression in the Nile tilapia, and suggests that this color is not adequate for holding containers for this species. Conversely, the present data show that blue light has a protective role against stress for this same species
Hormonal color changes could explain why with an increase in age/size dats often become more stable, and tend to show what most would consider dominant coloration, vs camouflage (sub-dominant concealment) vs younger, less mature dats kept under the exact same tank conditions. In some tanks fish take on more dominant, territorial behaviour early on in life, even as small juvies, and this could also very well be sex (and hormone) related.
None of the above is outside the norm for many species of fish that are kept in captivity.
Clearly there is no question that some dats kept in a stressful environment appear to be what many refer to as "stable", displaying dominant colors, and there are dats that kept in these exact same conditions appear to be "unstable", as in displaying dark camo/concealment stress pattern & coloration.
Perhaps some fish fall under the "fight" response, and some fall under the "flight" response. Same stimuli, but opposite reaction based on size/sex/dominance/tank mates/overall health etc-etc.
IMO the reason for no real definitive answer to the "stability" question, is that no single answer is correct for all fish, of various age/size/sex, kept under all of the various conditions possible in captivity.
This is why in Indonesia hobbyists will state: That is the challenge of keeping tigers - swee swee kim kim (stable) one moment and then suddenly "orh-orh". (black/unstable)
With datnoids, this just seems to be part of the enigma and challenge that makes keeping them so interesting.
