I can somewhat relate... I had a total of 3 green chromis for almost 2 months.. then suddenly had a wave of suicides
.. finding one dead on the floor one day followed by another the next day and then witnessed the third chromis attempt a suicide the third day, but luckily was there to pick him off the floor and toss him back in the tank.. and he hasn't attempted it since.. almost reminds me of the movie Final Destination.