I have had my 10 gal sorority tank for about a year and a half now. I started out with 6 females, and they all got along great. Then one died of unknown causes so I was down to 5. Then just recently the intake tube on my filter came off and sucked up another fish. Now I'm down to 4. Now that they are older, one of my fish has definitely become a bully. I finally decided she needed a time out so I put her in a breeder box inside the tank so she can still see the others but not chase them. I'm thinking of just taking her out completely and putting her in her own tank at my work or something. I am making a trip to petco tomorrow and I want to restock my tank. Is there a way to tell which females will do best in a sorority or is just luck of the draw? Since my 3 non aggressive females are older, will they pick on the new ones? I will quarantine the new ones of course by floating them in the tank so they can all get used to seeing each other. Any advice would be greatly appreciated!