It turned black in colour, then started sitting on the bottom of the tank, and then lost all ability to swim. The others look fine. What could have been wrong with it?
Probably just stress+nitrite poisoning . little fishy. To breed this fish you have to have low ph means 6-6.5 is perfect and ofcourse a pair of this that have been pair off. Its best to grow like 6 youngster from small size and work ur way up. Since they like to pair up by them self. And now all u can do is wait and provide the best water condition you could give no ammonia/nitrite/and a low lvl of nitrate, eventurally your hard work will get pay off. One day when u return home from work you will find a batch of happy little fry waiting for u in the tank . Good luck.
I have 3 Bolivian Rams. I came home last night and saw all 3 of them at the bottom and not moving at all, and all were truning black. Found out later that they were just sleeping. Scared me badly for them. They woke up and saw me and their colors came back. They and my 2 GBRs have character, like Oscars do—always coming up to the glass when they see me, and surrounding my hand when I'm doing something at the bottom, like moving rocks and vacuuming the gravel. They are my buddies. Other fish, like Madasgascans and Teras run for their lives.
As for yours, Rachel, being attacked by the other Bolivians, I wouldn't think so,`cos mine never attack eachother; but then again, there will always be one bully in the tank no matter how peaceful it's suppose to be. I have a Madagascan (a peaceful type) that's always chasing the other 3 Madasgascans, but it's just chasing, nothing violent, like 2 Jack Dempseys going at it.