Yupz. I tried to breed the cardinals before but I failed. There must be some conditions that might have gone wrong or I have yet to discover the trigger. Nevertheless, I have stopped trying now and just maintain that 4-foot tank as it is. My cardinals are tamed. Whenever I stand near to the tank, they will swim closer instead of swimming away. I have been keeping them for at least 3 years. I used to have 50 until one day they contracted ich. It is disastrous to contract ich. They were hit at least twice and I lost quite a lot of them. I have learned how to counter such calamity. I lost a few Yamato shrimps too.