the Keyholes will not eat small fish unless they are fry. It's fine. You could have a pair or 3 females . They are hard to sex so I would just get 2. Even if you get 2 males they are really good with eachother and will not fight. I had to males. I have just one now and he is 3 years old I love Carl my keyhole. When I had 2 males I never had problems they got along fine.