I have a rio 240 which is by no means overstocked and is also heavily planted with plenty of bogwood. I started off with two female Kribs as my local shop only had females. One of them quickly became very dominant and chased the other around the tank. A couple of weeks later I managed to obtain a mature male which then appeared to bond with the dominant female. Instead of getting rid of the other female I managed to obtain another young male. Now the large male has abandoned the dominant female and paired up with the other female. The two that have been left out have not yet paired up yet and the yong male spents its time hiding most of the time as the larger male seeks it out to chase it. Can any Krib Expert give me some advice. Mamy thanks Andy.