I have a 60 g cube tank. Inhabitants are 3 yellowtail damsels, 1 green chromis, 2 clownfish, 2 cardinal fish. About one month ago I added a 6 line wrasse. It was immediately chased into the rocks by one of damsels, and I have not seen it since. I few days later my fire fish was lost and haven't seen since. What is going on here ? Is it the damsels causing aggression ? I also have a 20 g tank with 2 clownfish and lots of like rock. I had a yellow goby in that tank and it slowly died from not eating. What is going on here ? I have 2 large freshwater tanks, and almost never lose a fish.