I need assistance. My tank holds 13.5 gallons. My first two fish were two ocellaris clown fish (the basic orange starter pack). After one of them killed the other, I followed the LFS's advise and began over with two new varieties of clownfish. Perhaps six months later, the frostbite clown killed the other. She recently killed the mandarin fish, so I've decided to leave her to be the clown solo. I'm at a loss on what to do. Is there a kind of clown that's friendly? Could it be that there isn't an anemone? Any suggestions for the future?