Good to hear... let me call off the shark police. j/k
Your bamboo will hide under caves/rocks unless he's looking for food. If you want him more visible, I have a couple suggestions. Try stacking your rocks in one corner of the tank, leaving enough room around the side and back for him to get through. This way, even when the shark is resting, he will probably be visible from the side of the tank.
The other suggestion is to spot feed the shark small amounts several times per day. In your tank the shark will become active when he is looking for food. If he is eating during the day, this is when he will swim and hunt.