Try some moist catfood, as in the foil pouch, preferably "seafood banquet" or such...it comes in various sizes such as cuts, fillets, niblets, etc.....if you have a cat, let the cat lick off all of the "gravy" and then use the leftovers.
If no cat, then place in a collander, strainer or similar and rinse thoroughly so as to was away any traces of anything greasy.
Add sparingly at first, then stand back and watch the magic.
While this may sound illogical at first consider any National Geographic special you've seen,"first we take this smelly concoction to draw the sharks in, called chum..."
Then consider that in the early hatchery days, salmon were actually reared on catfood, and lastly, some people use the term bamboo shark and cat shark interchangably.
What could be more logical for a "cat shark" than catfood?
My Brown Banded Bamboo Shark, "Bambi" is 13 months old (it hatched in my tank, so that's a precise measure of time) is approaching the 24" mark and while it eats many things the catfood is her favorite by far.