So, last week, I just bought some Rosy Barbs to keep my one male company. He was about six months old. Since I got them (I have a 40-gallon tank) They have all been dying off, one by one. Their tail(lol--almost said feathers!) gets a little ragged, and then they go belly-up. Did these new fish bring in some sort of disease? Should I have made a quarantine coop for them? Seriously, though, I'm kinda angry because I really liked the one fish who died.