The clown pair died within 12 hours of me introducing a tuxedo urchin. I have no clue what happened. They started panicking after I added that urchin. It was the most bizarre thing; no one could give me an explanation. This incident occurred nine months ago; the urchin is still with me. They were the only fish in the tank at the time.
The damsel pair coexisted in harmony for three months. However, one fine day, they decided to start hating each other. The bigger one kept the smaller damsel pinned to a corner and nipping at it. I rehomed them within 2 hours of them starting to fight. I was fighting dinos (first round) when this happened and was feeding pellets four times a day. Once the dinos backed off, I cut down feeding to only once or twice a day. This could have been the triggering event. Once again, they were the only fish in the tank.
The cardinal trio has been in the tank for over five months now. They just hang out all day and are not mean. However, the biggest one gets the first picking when I feed the tank. They are not very active and hence do not need a lot of space, and the red eyes are a cool touch.
About a month back, I added a diamond goby. He is a character. He was timid at first and would not come out of his cave. It took a few days for him to be gain enough courage to explore the tank. Then my friend visited, and that was too many 'vertical sharks' in the room for the goby. It went into hiding for another week or so. lol. He has become very bold now and begs for food around tank feeding times (still scared of the algae scrubber).
It has been quite a journey. I battled dinos twice in one year and had months of only bad things happening in the tank. Those experiences have made me more confident now and gave me a better understanding of things.