Been keeping track and it's been 7 months since deciding to try yellow tail damsals. Never had any luck with chromis. I wanted some nice blue color to the tank and was told at LFS that these were the least aggressive. To date, none have died and they are not the least bit aggressive to each other or the other tank mates. They look extremely cool swimmin around, and if anyone ever comments on fish in my reef, its usually about these guys, cause they look so nice swimming together. Thumbs up. I'll keep you posted.