I didn't want to get just a pair of EBJD's since I have read that you should either get 1 or 3 or more and never pairs.
You have received horrible advice and should therefore question anything you read from that source...
There is nothing wrong with keeping a single Blue Dempsey...
Dempseys are pairing fish, and there is not reason not to keep a compatible male & female pair. It is true that a Blue male and a Blue female will produce exceptionally weak fry that do not survive, if they breed at all... but you have not said anything that indicates you whish to breed...
Two or more male Dempseys, Blue or not, are very unlikely to co exist as adults...
Keeping 3 females might work, might not. Chances are the dominant female would spend her live suppressing the subdominant females leaving them stressed.
If kept as a male, a female and a third wheel of either gender... the third wheel will be suppressed by the pair leaving it stressed if not damaged and possibly killed.
Dempseys are not "colony" fish to any degree and keeping them as such (as adults) will almost certyainly result in the smaller of the group being heavily stressed by the mid range of teh group who are stressed by the dominant fish of the group.
I have grown out Juvenal groups together on several occasions, but as soon as they reach sexual maturity they are split up. I have had adult male Dempseys fight one another when kept in the same tank just like I would expect any two male Dempseys to fight.
Keep in mind, their nature is no different than a standard Dempsey... they are just Blue and come from a little weaker genetics...
