feeding and clown knives

Question
i recently added fish to my 55 gallon tank, i have 4 bala sharks, 2 clown knives, and 2 tiger catfish. i'd like to know when is it time to start feeding the sharks and clowns live fish? right now i just started giving them frozen brine shrimp. also one of my clown knives is always hiding, i've only seen him eat maybe once this week. any ideas? thanks for taking the time to respond! i love the site

Answer
We have an eel, that we have had for about 6 months, we have never once seen this thing eat!  It somehow is living and growing!
I sometimes think fish are similar to people, they have different eating habits, different personalities.
Now, having said that, I certainly can not assure you there isn't anything wrong with him, I just wanted to let you know it doesn't mean for sure there is something wrong with them.
Personally I would not feed them live fish unless you are raising them yourself.  That is a good way to enter disease into your tank.
Good luck!