Can I keep cardinal tetras with a black ghost knife fish and two African butterfly fish?

I would like to keep two African butterfly fish and one black ghost knife fish (3inches) with cardinal tetras and xl penguin tetras. Is this ok or will the tetras get eaten.|||African butterfly fish, also known as Pantodons, have very large mouths and will easily swallow a cardinal tetra. At the price of cardinal tetras, I would not suggest it. Some fish stores say that you can keep neon tetras with black ghost knife fish but in my experience the black ghost knife will usually eat the neons. You might get lucky and get one that does not but again your chances are not good. A three inch black ghost knife is just a baby so if you can get neons cheaply enough start with a big school and if they don't disappear you can add a few Cardinals from time to time. I used to be able to buy small neon tetras for 20 cents each. Now they are about $2 each. Depending upon the size of your pocket book and the size of your tank it might be worth the gamble.|||Black ghost knife fish (Apteronotus albifrons) usually grow to around 30-35cm in length and they are quite capable of consuming small fish such as Tetras. However the Butterfly fish should be large enough not to be eaten. You could try the larger Rasbora species.|||it will be fine as ghost knifes are very slow moving fish and will not be able to catch the fast moving tetras. butterfly fish are quite peaceful|||It would be okay, but ensure your black ghost doesn't get too big, as it can consume tetras.